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Three approaches to units of mass and force or weight[1][2]
Base Force Weight Mass
2nd law of motion m = F/a F = Wa/g F = ma
Acceleration (a) ft/s2 m/s2 ft/s2 m/s2 ft/s2 Gal m/s2 m/s2
Mass (m) slug hyl pound-mass kilogram pound gram tonne kilogram
Force (F),
weight (W)
pound kilopond pound-force kilopond poundal dyne sthène newton
Pressure (p) pound per square inch technical atmosphere pound-force per square inch standard atmosphere poundal per square foot barye pieze pascal


Nobody uses kilopund in the metric system! Force is all ways newton in the metric system. It does no matter if "Gravitational", "Engineering" or "Absolute". It's may not easy to understand for Americans and Britannia's... :-) But it is the true!-- (talk) 14:57, 12 November 2008 (UTC)

Keep in mind that the metric columns are not SI, exept for the absolute column. Also, the other name for a kilopond is a kilogram force, which is probably used somewhere(maybe if only on those machines that tell you how much you weigh on another planet)ArkianNWM (talk) 23:54, 21 April 2009 (UTC)


Three approaches to mass and force units
System Gravitational Engineering Absolute
Force (F) F = m·a F = m·a/gc = w·a/g F = m·a
Weight (w) w = m·g w = m·g/gc ≈ m w = m·g
Units English Metric English Metric English Metric
Acceleration (a) ft/s2 m/s2 ft/s2 m/s2 ft/s2 m/s2
Mass (m) slug hyl pound-mass kilogram pound kilogram
Force (F) pound kilopond pound-force kilopond poundal newton

The entire graviational category makes no sense. There is no real difference between the English systems using slugs and lb-f versus lb-mass and poundals; the only difference is what quantity was scaled to account for the acceleration of gravity. Why should one be labeled "gravitational" and the other "absolute". They are both absolute systems with only minor differences between them. The same goes for the metric alternatives as well. I believe the table should be changed to reflect that. Not to mention that slugs/lbs-f are more commonly used in engineering applications and in the sciences that use the imperial system, anyway.ArkianNWM (talk) 19:44, 14 April 2009 (UTC)

You are right that they’re both absolute systems since 1 poundal = 1 ft·lbm/s2 and 1 slug = 1 lbF·s2/ft, i.e. unity everywhere. The difference is the selection of base unit: mass (“absolute”) or force (“gravitational”). The table should make that cleare, but I don’t know how.
It makes sense (for me) to interchange the column headers “gravitational” and “engineering”, because only in the middle column gC, i.e. a gravitational constant, is important. It may be an older glitch that nobody else noticed or bothered enough to correct. — Christoph Päper 22:07, 26 July 2010 (UTC)
Well, I've just made an attempt at fixing it. Also fixed the misuse of "English" as a synonym (in the USA only I believe) for the FPS (Foot-Pound-Second) system. Who the h*ll thought that the Hyl was a metric unit of mass anyway?? Sheesh. Steve Hosgood (talk) 11:33, 25 November 2010 (UTC)

FPS gravitational? Not aware of any sources that call it that -- there are multiple sources for "English Engineering." Included citation of one of them. Gerardw (talk) 00:35, 11 June 2011 (UTC)

FPS is by definition gravitational because its basic unit is force (mass under the influence of gravity), with mass (slug) derived. SI is an absolute system because mass is its base unit (force is derived). [Ref: Shigley].
gc is not a gravitational constant in the usual sense (acceleration due to gravity at the surface of the earth, or g0=9.81m/s2=32.17 ft/s2), but an arbitrary non-dimensional factor to try to get a dodgy system of units to work with Newton's 2nd law. There are in reality only two basic systems, derived by pound, foot and second (FPS) and kg, metre and second (SI). There are other derived system of both, such as inch,pound,second (IPS) but they aren't fundamental systems in themselves. Units like "pound-mass", "pound-force" and "kilogram-force" were invented by people who didn't understand the basic systems. That's the reason why textbooks (such as Shigley) use "pound" and "pound-force" terminology interchangeably because they are in reality one and the same (lb=pound=pound-force) and textbook authors do understand the basic systems. Difference in terminology shouldn't be confused to create entirely different and ficticious system of units. Pound is a force. It happens to have a conversion to a mass that is often spouted on Wikipedia talk pages as proof that it is a mass, but that assertion on a conversion alone is misguided. Pound-mass is as much a misnomer as kilogram-force. Any systems of units derived from these misnomers are also false and should be removed from Wikipedia for lack of sufficient credible sources. — Preceding unsigned comment added by (talk) 09:59, 29 September 2011 (UTC)

Names and sourcesEdit

Whatever we call these things should have a RS. I agree the one I found isn't the best but it is better than nothing. If editors want to use different names they should cite sources to support them.Gerardw (talk) 13:51, 21 September 2011 (UTC)

British Gravitational English Engineering Systeme International (SI)
Engineering, absolute Engineering, gravitational Science, absolute
Source has this:
Mass and Force Units
dimension: mass force
Systeme International units kilogram (kg) newton (N)
British Gravitational System units slug pound
English Engineering System units pound mass (lbm) pound force (lbf)
There’s nothing British about the first column, look at its sub-columns labeled English and Metric. There’s also nothing specifically English about the second and the last one covers many (sub)systems, not just SI.
We should probably use terms like absolute, gravitational, coherent, consistent etc. to label the columns, though not necessary to name the systems.
Upon googling I’ve found some more instances (esp. from websites for engineers) that differentiate the SI from BG (British Gravitational System) and EE (English Engineering System). The Civil Engineering Reference Manual for the PE Exam by M. Lindeburg also covers the third English system, calling it the “Absolute English System”, and “obscure”. On [1] I found this definition: “When a coherent system is built from a basic unit set which includes mass, the system is called absolute. If the basic unit set includes force, rather than mass, the system is called gravitational”, but it doesn’t say how to call the middle column as far as I can see.
I’ve not found a source that lists as many systems as this table comprehensively. This template will be a collections of information from other articles, based on many sources and I will now edit it once again. — Christoph Päper 13:08, 22 September 2011 (UTC)
Any system of units that violates Newton's 2nd Law (F=ma) does not deserve any reference to "engineering". As an engineer, I use either slug,pound or kg,N (mass,force) regardless of what their associated unit systems are called. I would hope that those who are chopping and changing the reference to the various FPS systems as being "engineering" are in fact qualified to do so and not just putting blind faith in what appears to be nothing more than university exam study notes (I can vouch from my own university engineering experience that notes written by lecturers are full of mistakes). I would like to contend that the middle column that uses the gc constant isn't really a system of units at all. This system has somehow popped up on an important Wikipedia article with little to back it up. I'm ready and willing to be proven wrong of course, but only with reliable sources and practical experience to back up the contender; armchair experts need not apply. — Preceding unsigned comment added by (talk) 09:25, 29 September 2011 (UTC)
Incoherent systems are stupid, but popular in colloquial, informal usage and – let’s face it – engineers are the most informal among all scientists. I don’t really care whether the first column is called “gravitational”, “technical”, “engineering”, … or the second “colloquial”, “media”, “naive” …, as long as the table makes sense as a whole. Nevertheless you will find many sources, including reliable ones, for the terms “British Gravitational” and “English Engineering” as used herein (now), even if they are certainly not the best names one could come up with.
As for the validity of the middle column, I can assure you that kilogram and kilopond were used a lot together (and somewhere still are), e.g. by Wernher von Braun, at least much more than the hyl or TME with either of them. Even if the two faces of the pound were not used together as frequently that would not invalidate the approach, as foolish as it may be. — Christoph Päper 17:07, 29 September 2011 (UTC)
FPS is gravitational, SI is absolute (Ref: Shigley). There is no such thing as an "engineering" system of units because engineers use both FPS (Imperial) and SI (Metric). If you don't understand the meaning of these things then you aren't really qualified to comment on their use/definition on Wikipedia (don't mean to be harsh).
Not doubting the use of derived/informal units (kilopond is an "informal unit of force" Kilogram-force) but they don't constitute a fundamental system of units by themselves. Perhaps it could be in the table somewhere, but it deserves only secondary mention. The table should highlight the primary basic systems of units unambiguously. — Preceding unsigned comment added by (talkcontribs)
The slug variant of FPS is called, at least by some people, engineers actually, “gravitational”, the poundal variant is not. Some of the same people who call the FPS variant from the first column “(British) gravitational” refer to the FPS variant from the second column as “(English) engineering” – I wouldn’t choose either of these terms, I’d rather call the double-pound variant “gravitational”, but that doesn’t seem common. Some people – including yourself, it seems – only consider their preferred variant as “FPS”.
Several sources connect “absolute” to the principle the mass unit is a base unit – I would call every system without arbitrary factors and constants an absolute one, i.e. everything in the first and third column.
Like I said, I don’t care which column one is called “Engineering” here or elsewhere, especially since pretty much every contemporary engineer in the world (except in the US) uses the SI. We just need three somewhat descriptive column labels. Please suggest better ones, and stop ad hominem attacks.
The primary intention of the table is not describing the actual systems of units, but to highlight that there are (at least) three possible approaches to design one. — Christoph Päper 20:27, 29 September 2011 (UTC)
FPS is the fundamental gravitational system of units (the metric version in the table is merely derived from the absolute metric system). As stated previously there is no such thing as an "engineering" system of units, regardless of their use by engineers (I'm an engineer by the way). Dispite previous claims, most engineers are fluent in both Imperial and Metric systems, readily and regularly converting between the two. Claiming that "pretty much every contemporary engineer in the world (except in the US) uses the SI" is false and misleading. If you are going to make claims like that, at least back them up with a reliable source. The two types of systems should be labelled "gravitational" and "absolute", the the third (middle) column deleted as it doesn't describe a system of units, but includes reference to made up derived or informal units that even combined don't constitute valid systems (if you insist they do then please cite reliable sources). A "poundal" is also derived. Shigley defines two types of systems, and it is a reliable source. If the intention of the table is to highlight approaches to designing a system of units, then there are still only two approaches; gravitational (force, length and time) or absolute (mass, length and time). As an engineer I don't call a system of units "gravitational" or "absolute"; I call them Imperial and metric, and use of such terminology is unambiguous (including outside the engineering profession). You may call "every system without arbitrary factors and constants an absolute one", but that is irrelevant unless you can back it up with a reliable source. — Preceding unsigned comment added by (talk) 03:03, 30 September 2011 (UTC)
There’s no empire, yet you call it “Imperial” – it’s the same with “Engineering”, just a label someone once established more or less successfully and appropriately. If there’s a better one we can certainly use it.
The whole point of the middle column is that it’s scientifically stupid, but possible, to use an incoherent system (“weight, length, time” if you wish), which is very common nevertheless, e.g. in mainstream media. The table would make little sense without it. The distinction between “imperial” and “metric” is of course irrelevant for the top row, and insufficient, i.e. ambiguous, for the rest.
I don’t understand your first sentence, by the way. There are “gravitational” and “absolute” variants of the FPS (and the metric) system, even though in your world the pound may be used primarily as a unit of force. — Christoph Päper 08:15, 30 September 2011 (UTC)
Base force, length, time weight, length, time mass, length, time
Type coherent, gravitational, technical incoherent, colloquial, pre-newtonian coherent, absolute, scientific
I didn't imply that the columns should be titled "Imperial" and "Metric". I merely countered your frivolous claim that engineers generally refer to FPS as "gravitational". Imperial an metric are the common layman terms for the two systems (and your claim of imperial and metric being ambiguous is equally unjustified). The first sentence of my previous comment that apparently confused you was merely to highlight that metric/SI is fundamentally an absolute system of units. Of course its possible to artificially create a gravitational system from it. My world (and that of the rest of the engineering fraternity) has a big influence on your world believe it or not, and our understanding of these units helps keep you safe. Have you ever actually used any of these systems that you are claiming authority with regard to? Your arguments seem pretty desperate, with nothing in the way of experience or sources to back you up. If you have some, please put them forward. They will hold more weight than ranting ever could. — Preceding unsigned comment added by (talk) 08:48, 30 September 2011 (UTC)
Base force, length, time mass, length, time
Type gravitational absolute
Known as Imperial Metric/SI
Mass slug (derived) kilogram
Force pound Newton (derived)
Length foot meter
Time second second
Pressure psi or psf Pascal

There, can't get much simpler than that. Words like "technical" and "scientific" or "engineering" are irrelevant/not required. Engineers and scientists use both. Neither is more technical than the other. This simple version of the table is easily sourced (Shigley for example, or many other text books). If you want to add apparently supurfluous buzz words, I suggest you come up with a source to back them up. There are of course other units (inches of mercury for pressure for example), but they are generally converted for application of the physics laws (or make use of factors and emperical formulas). — Preceding unsigned comment added by (talk) 09:05, 30 September 2011 (UTC)

Yes, a pound is equal to 0.453 kg (on the surface of the earth). This table doesn't contradict that. Disbelievers should look up the definition of "unit conversion". — Preceding unsigned comment added by (talk) 09:13, 30 September 2011 (UTC)
As the template is used on the Pound (force) page, the column with lbf needs to remain. The source I previously provided documents this usage and I assume the current source does also. Gerardw (talk) 11:05, 30 September 2011 (UTC)
This template would be complete if it used just the first four rows of its current version. Metric and English units and systems are hardly more than examples. Its (prime) purpose is not yet another English / metric comparison.
You can’t disqualify yourself more – writing anonymously helps – than by saying something like “a pound is equal to 0.453 kg (on the surface of the earth)”. That’s the middle column. — Christoph Päper 19:14, 2 October 2011 (UTC)
Please clarify the antecedent of the pronoun "You" in your statement You can't disqualify yourself more. Gerardw (talk) 19:31, 2 October 2011 (UTC)
It refers to the IP user. — Christoph Päper 07:51, 3 October 2011 (UTC)
The problem with the table is that it appears to (attempts to) qualify various units as members of their own fundamental system, except that most are merely derived from the basic metric or imperial systems. If you are going to list all the various units that could be used in their various combinations within each system, then you are going to need a much larger table (refer to the convert program written by Josh Madison - http://joshmadison.com/convert-for-windows/). Perhaps the problem is that the purpose of this table hasn't been agreed on. If it is to define the fundamental systems, then they are basically imperial and metric. What other purpose could it possibly serve? If you want to list all the constituent units of each system, the current table is incomplete. If you want to include obsolete/incoherent/informal/make-beleive systems for posterity or historical purpose, then I suggest they be isolated as such so as not to be confused with the two fundamental systems (which has already occurred in discussions on Wikipedia talk pages). The conversion you "disqalify" is between a force (lb) and a mass (kg). This is the same as the middle column, but is also why the middle column isn't a "system" on its own; the middle column just the imperial (first) column with a new mass unit (lbm) equated to the imperial force unit on the surface of the earth (and as such the "system" is only valid at the surface of the earth). Imperial force is denoted either "lb" or "lbf" (both are acceptable), which can only possibly be confused when "lbf" is conflated with the absurdity of the pound mass (lbm), as is the case in the table. Leave the middle column if you wish (I'm not going to bother changing it as it will just be reverted anyway). — Preceding unsigned comment added by (talk) 02:05, 3 October 2011 (UTC)
Even rocket scientists (well, rocket engineers, at least) use pound mass [[2]] Gerardw (talk) 02:41, 3 October 2011 (UTC)
That's funny because my qualification is aerospace engineering. I never been employed in rocketry (only aviation) but I don't remember seeing pound mass in any equations in the space subjects. I had a squiz at the NASA page. Not sure why it wouldn't use slug, but things are measured in pound (force) on earth's surface. Perhaps the experts on the subject (of pound being a mass) can explain how you get an incoherent system of units to work with a formula based on Newton's equations of motion? For example, Shevell (already referenced at Slug (mass)) gives TSFC in lb/lb-h (figure 17.8, page 339). Oddly enough, the NASA page examples are the same, with pound being treated as a force, the pound numerator cancels pound denominator resulting in their dimensionless (hr-1) TSFC values. There's a nice table that sort of looks like the sample I came up with above here ([[3]] - author appears to be a physics PhD with a bad sense of humor [[4]]) under the section titled "VII: PHYSICAL UNITS: MECHANICS". This page has already been mentioned in an earlier comment by Christoph Päper. Also, have a careful read of the section titled "IV: COHERENT UNIT SYSTEMS". — Preceding unsigned comment added by (talk) 08:02, 3 October 2011 (UTC)
Also keep in mind that just because something is on a NASA-hosted page doesn't mean its what rocket scientists use. Most NASA rocket engineers work as contractors (Rocketdyne, Boeing, Lockheed Martin, Grumman, etc). NASA employees are mainly bureaucrats and academics. — Preceding unsigned comment added by (talk) 20:50, 3 October 2011 (UTC)


Per WP:RS, I've reverted the table to titles which have references, adding a third. Gerardw (talk) 19:00, 24 November 2011 (UTC)

You again labelled generic columns with terms specific to English units. Please stop!
I’ve kept the reference, though, because it names some of the terms in the sixth row (abbreviated “BG”, “EE”, “SI”), i.e. the labels of the split columns. — Christoph Päper 11:31, 25 November 2011 (UTC)


Should the top of the table use option "one" or "two" below?


Three approaches to mass and force units[3] [4]
Base force, length, time weight, length, time mass, length, time
Designations gravitational, technical colloquial, pre-newtonian absolute, scientific
Type coherent incoherent coherent


Three approaches to mass and force units[3] [4]
Base force, length, time weight, length, time mass, length, time
Designations British Gravitational System[5] English Engineering System Systeme International
  1. ^ Comings, E. W. (1940). "English Engineering Units and Their Dimensions". Industrial & Engineering Chemistry. 32 (7): 984–987. doi:10.1021/ie50367a028.
  2. ^ Klinkenberg, Adrian (1969). "The American Engineering System of Units and Its Dimensional Constant gc". Industrial & Engineering Chemistry. 61 (4): 53–59. doi:10.1021/ie50712a010.
  3. ^ a b Lindeburg, Michael, Civil Engineering Reference Manual for the PE Exam
  4. ^ a b Wurbs, Ralph A, Fort Hood Review Sessions for Professional Engineering Exam (PDF), retrieved October 26, 2011
  5. ^ Avallone, Eugene; Baumesiter III, Theodore (1978). Marks' Standard Handbook for Mechanical Engineers (Ninth ed.). p. 1-25. ISBN 0-07-004127-X. {{cite book}}: Cite has empty unknown parameters: |trans_title= and |month= (help)
Both rows in question have been removed temporarily from the table. — Christoph Päper 08:54, 2 December 2011 (UTC)

Two This options utilizes titles supported by WP:RS. Option one titles are not supported by references and are not NPOV, specifically "'colloquial, pre-newtonian". The second line of option one, "coherent / incoherent", is also POV. The general English connotation of "incoherent" is 'illogical' or 'nonsense.' However the use of the term incoherent by a source in one of the articles is used in the denotative sense of "incomplete," as English Engineering does not define all seven base units. While a note to the effect is appropriate for individual articles, including in a summary table is WP:UNDUE. Gerardw (talk) 12:51, 27 November 2011 (UTC)

I would go with Two because the coherent/incoherent distinction is related to the system of units, not the approach to mass and force. I would however drop the second "e" in "Systeme", and link the system terms. Rich Farmbrough, 13:21, 27 November 2011 (UTC).
To clarify -- do you mean, for example, link System Internal to the SI article? Gerardw (talk) 13:33, 27 November 2011 (UTC)
Yes. Rich Farmbrough, 15:27, 2 December 2011 (UTC).
The titles supported by the sources as advocated by user:Gerardw are used appropriately in the later row labeled “System”, but are abbreviated due to width constraints. A column title like “British Gravitational System” is obviously not valid for covering “BGandGM”.
The terms coherent and incoherent are used in the “physics sense” (also used by the sources cited in the template), i.e. you have base units (and dimensions) and derived ones (e.g. basic length and derived area), so you can either derive the force unit from mass or vice versa, but the approach described in the middle column does neither, therefore it’s not coherent. Although an electromagnetic base unit is required for a complete coherent system, it doesn’t matter for this table which only covers classical mechanics.
I’ve said before (see above) that I’m keen on neither the exact contents nor the presence of these two rows, but what is proposed in Two is just wrong. — Christoph Päper 08:54, 2 December 2011 (UTC)

One of course, because the designations in Two are simply misnomers since the difference between the columns – not visible in the excerpt above – is not British / English / Imperial / US versus international / metric unit systems, but force versus weight versus mass as a base unit. I don’t care much about the Designations row, neither its contents nor existence, as long as it not incorrectly uses geographic terms like English or International which simply not apply. — Christoph Päper 10:25, 28 November 2011 (UTC)

The geographic terms are part of the proper names of the systems of units, and are not, strictly speaking, referring to any actual geographic connections. British Gravitational Units, SI, and English Engineering units just happen to be what these systems are actually called, and are therefore not incorrect. siafu (talk) 18:23, 2 December 2011 (UTC)
They’re incorrect in so far as the columns cover both, English and international instantiations, so we must use generic column labels – or none as is the case currently. I really am puzzled how that can be non-obvious to anyone who looks at the table (and not just the excerpt at the top of this section).
The actual system names (including toponyms) hide themselves in the acronyms. They’re not that important here, so we can keep it that way and people can follow the links if they want to learn more. — Christoph Päper 20:12, 4 December 2011 (UTC)

Two of course, as per Rich Farmbrough. — Dmitrij D. Czarkoff (talk) 08:35, 30 November 2011 (UTC)

If I understand both of you correctly, you’re advocating to remove the “Type” row, but say nothing about the “Designations” row? — Christoph Päper 10:10, 30 November 2011 (UTC)
The RFC gave two options: One, with designations which are biased and not supported by references, and Two, which deletes the coherent/incoherent column and is supported by sources. They're selecting option Two. Gerardw (talk) 03:51, 2 December 2011 (UTC)
Indeed. The RFC is a binary choice, of the two I find the second more usefu, evaluating the template in isolation. If a more open question were posed I might suggest that the names of the rows need more thought - so in Two instead of "designations" "Systems that use this method" might be better, or just "Systems". Similarly part of the "designations" in One might be better labelled "Fields using this method" though I suspect most large fields will have used all three at some point in time. With the GravEngAbs designations it might be well to be more explicit, "Gravitational : the unit of force is based on the unit of weight acting through the unit of length". In summary the table should show important differences between the three systems in a way that will make sense to the average reader of the articles. The existing template does seem (looks) pretty good if proper math layout were used instead of the sub-tables for the formula. Rich Farmbrough, 15:27, 2 December 2011 (UTC).
Not only that, actually. The first option is entirely overdetailed, it needs further detail. If the discussion was over the article, I would suggest a way to unify the options, but for the template being explicit and informative for reader is a clear and substantial benefit. The option two gives the needed context and require less explanations, so it's a clear winner. — Dmitrij D. Czarkoff (talk) 10:05, 2 December 2011 (UTC)
Then we’re back to this version, which – despite being the source for the template’s name – has also been questioned a few sections above. That discussion resulted in version One. — Christoph Päper 10:29, 2 December 2011 (UTC)
Three approaches to mass and force units …
Base force, length, time weight, length, time mass, length, time
Designation Gravitational Engineering Absolute
  • Two Option one really requires so much further explanation in the accompanying text that it loses its utility and illustrative power as a table, really. siafu (talk) 18:23, 2 December 2011 (UTC)
Then I suggest we either remove the rows in question altogether (which is what I’ve already done) or we just use “Gravitational”, “Engineering”, “Absolute” like the template did originally. — Christoph Päper 20:12, 4 December 2011 (UTC)
Is there a reliable source which uses these labels? Gerardw (talk) 20:21, 5 December 2011 (UTC)
The first two are what you proposed, freed of toponyms. You’ll find tons of sources for “absolute” referring to mass-based systems exclusively, although I would apply it to any system of units that derives its other units without using arbitrary factors like 12 or gc. See the discussion above, initiated by an IP user who was offended by the “Engineering” label, that lead to the change to One. Anyhow, I don’t have a source at hand which compares and labels approaches to unit systems instead of their instantiations. — Christoph Päper 15:19, 6 December 2011 (UTC)

neither. weight is ambiguous so the middle columns on both are not required. the buzz word fetish (engineering, technical, scientific) is just rediculous. (talk) 01:06, 15 March 2014 (UTC)

Take a fourth option?Edit

Mass, acceleration, and time. Define the length unit as g * (time unit)². Then you have a system where weight numerically equals mass (like English Engineering units), but is also coherent. This is the approach used by Tom Pendlebury's "TGM" system. - DanBishop (talk) 08:24, 29 April 2012 (UTC)

Not familiar that system -- are their reliable sources for it? Nobody Ent 21:58, 29 April 2012 (UTC)

Eliminate pound mass because it's not part of a real system of unitsEdit

Just get rid of the pound mass already. It's not a real unit of mass. It's not a real unit of anything. It's merely the result of some people confusing pounds (as a force, and not "pound-force" or whatever other versions of pound there are) with mass because they use it for comparing weights on the surface of the Earth. The middle column is not a coherent system of units (which means it doesn't work with Newton's 2nd law) and "weight" is ambiguous unless you're a engineer or some other technical person (engineers treat "weight" as a force equal to mass x acceleration due to gravity). Imagine a unit of "mass" that has to be arbitrarily divided by a "constant" that just so happens to equal acceleration due to gravity on Earth's surface (which means you're stuffed if you take your pound-mass calibrated scale to the moon) and even requires modification of Newton's 2nd Law of Motion (F=ma => F=ma/gc) to convert to it's own unit of force ("pound-force")! Pound (just pound, not pound-force) is a force, and that's all there is to it. Pound (as a force) combined with it's associated derived and coherent unit of mass (the "slug") works fine without any modification of the laws of physics or constants or mixing up with weight etc. It just works. Engineers treat pounds as a force because it works. If you think of pound as mass and try using it in any sort of equation you will always run into trouble. I get that if you are weighing things in pounds it kinda seems like a mass, but remember that you are "weighing" (weight=mass x gravity=force), not "massing". I have no doubt that pounds converts to kilograms, but so does Newton if you take gravity into account (as you do with pound-mass via the gc constant). Why are some people so insistent on pound being a mass? I feel sorry for other people that may read Wikipedia articles with the garbage in this template and mistakenly believe that it has merit. (talk) 22:17, 11 July 2013 (UTC)

Um, this template shows what possibilities there are and, in fact, most of them have been in use at times by more or fewer people. Since the table is not intended to show some best way of doing it – pounds of any kind would‘t appear then – there’s absolutely no reason to remove pound-mass or anything else. It’s complete like it is now. — Christoph Päper 22:58, 11 July 2013 (UTC)
From my own experience FPS (pounds treated as a force) is as easy as the metric system. It would only seem confusing to someone who has never used it or doesn't understand it (and if that person reads anything on these Wikipedia pages they will come away even more confused). That's my contention regarding how Wikipedia has addressed the FPS system; it hasn't, and will continue to perpetuate confusion. It is very simple; treat pound as a force (as it is) and all problems/confusion with FPS go away. Slug is the derived FPS mass. This stuff has been used in aviation for over a century and will continue to be used in the foreseeable future. There's no need to worry about lbf, pound-force, pound-mass (whoever thought that one up needs to be shot) etc. Pound is just pound (lb). You can weigh things in pounds, and the value you get is a force. You can convert that force to a metric mass (kg) very easily using acceleration due to gavity and Newton's 2nd law. If you took earth scales to the moon the conversion would no longer work, which is an easy way to demonstrate why even the pound scale on weight measuring devices is a force (not to mention pressure gauges in psi or torque wrenches in ft.lb etc). I know I'll never convince some editors on Wikipedia, hey at least I'm trying. (talk) 04:36, 30 November 2013 (UTC)


Three approaches to English units of mass and force or weight[1][2]
Base Force Weight Mass
2nd law of motion m = F/a F = Wa/g F = ma
System British Gravitational (BG) English Engineering (EE) Absolute English (AE)
Acceleration (a) ft/s2 ft/s2 ft/s2
Mass (m) slug pound-mass pound
Force (F),
weight (W)
pound pound-force poundal
Pressure (p) pound per square inch pound-force per square inch poundal per square foot

I don't understand. The standard unit symbols for pound (mass) and pound force are lb and lbf, respectively. What is the benefit in introducing non-standard symbols? Dondervogel 2 (talk) 00:29, 14 December 2016 (UTC)

There’s nothing like the standard regarding pounds. This table tries to help explain why some people think ‘lb’ is a unit of force, some think it’s a unit of mass and some don’t get the difference because they think it’s a unit of weight used for both, mass and force, with little to no discrimination.
See, I don‘t disagree with you that Wikipedia should adopt a universal, coherent style for units and their symbols. (I’d prefer metric-only.) All modern standards (and the legal definitions) agree that pound, like kilogram, is a unit of mass. In science, almost universally, the last column is favored. There’s no disambiguation necessary within that system, but that’s also unnecessary within the system shown in the first column. If the system in the middle column is used with adapted formulas, it actually doesn’t need disambiguation either. Only if you have a mixed use of systems, as you do in reality, you need to distinguish different kinds of ‘lb’. Making ‘lbf’ the special case in the middle column would introduce a distinction that is not made within the system, by applying a convention from the last column. We’d need to change the symbol to ‘lbf’ in the first column then, too, which would be even more revisionist.
In conclusion, unique, unambiguous symbols make sense where the units are used with numbers, but not when they themselves are described as is the case in this template.
Note, though, that ‘lb’ would only be unique by convention, but still ambiguous in isolation, i.e. without either ‘lbf’, ‘pdl’ or ‘slug’ to contrast with it (or other context). That means, for the MoS, it would probably make more sense to adopt any pair out of lbm:lbf, lbm:lbf, lbm:lbf, lbm:lbF, lbm:lbF and, paralleling SI’s kg:N, lb:pdl than the inconsistent mix of lb:lbf (or any other way of typesetting the F). Using indices for both follows a higher-level standard than choosing one convention over the other. — Christoph Päper 12:20, 14 December 2016 (UTC)
By "the" standard I was referring to the only international standard[3] I am aware of that has something to say on the matter (see discussion at mosnum). With the present notation, I am unable to comprehend the table, so in that sense I am still confused. Please feel free to join the above-mentioned mosnum discussion. Dondervogel 2 (talk) 13:21, 14 December 2016 (UTC)
The table now uses lbf for pound-force except in the BG system. My instinct is to use lbf there too, for consistency with the other columns (and the IEEE standard) because I think this would be less confusing. Any objections? Dondervogel 2 (talk) 19:27, 15 December 2016 (UTC)
I tried to explain why this would be stupid (and will revert now). The columns need internal consistency. It would actually make more sense to drop the indices from the middle column altogether, so ‘lb’ would be used everywhere. — Christoph Päper 09:11, 16 December 2016 (UTC)
I tried to explain why I find the table incomprehensible in its present form. For example, what is the difference between the units denoted lb in the BG column and lb_F in the EE column, or between lb_m in the EE column and lb in the AE column? Baffled as always, Dondervogel 2 (talk) 13:10, 16 December 2016 (UTC)
I merged the cells in the middle column, I hope this makes it more clear. Distinction by suffix or index kept in tooltip (title attribute). — Christoph Päper 03:55, 24 December 2016 (UTC)
No, that doesn't help at all. I prefer the previous version, by DickLyon. The kilogram (kg) is never a unit of force, there's no such thing as kgm, and the international standard symbol for the pound force is lbf, not lb. I'm now not sure whether the table represents units or unit symbols. In its present form it's so confusing I would prefer to delete it than keep it like it is. As a provisional measure I will revert to DL's version, and we can discuss improvements to that here. Dondervogel 2 (talk) 11:21, 24 December 2016 (UTC)
A system in which mass and force have the same unit is perfectly legitimate. This is not, however, the system that was originally intended to be displayed in the middle column. In the latter system mass and force units are different, and nothing should be done to confuse it with the former system. Using the same symbol for both units creates such a confusion, and adding the tooltip only makes matters worse. The statement by Crissov on the revision history page that "in systems like EE, mass and force units are hardly distinguished" makes no sense; units are distinguished or they are not, and there is nothing in between; his statement that units should be distinguished is merely a value judgment. It should also be said that each unit stands by itself, and its symbol should not allude to other units; in particular, symbols for units should not have subscripts. Similarly, each system of units stands by itself and should not allude to other systems; in particular, the same symbol may have different meanings in different systems. International standards for symbols are irrelevant in this context, since they were not created with a particular system in mind. One should follow the practice of the major literature on the subject; for EE this is the paper by Comings. Since it is difficult to obtain information on EE, the references in the template should not have been deleted. (talk) 16:40, 7 October 2017 (UTC)
The major point of this template is to show that the English pound, lb, is used as either a unit of mass or force or both. When used as a unit of force, it is sometimes written with a suffix or index (i.e. F or f or -force), but not always. Much less often, a disambiguating suffix or index (m or -mass ) is also or instead encountered when the pound is used as a unit of mass.
This template cannot simply follow "practice of the major literature" because most literature uses one system consistently internally but in a way that does not distinguish itself from other systems all the time. If you encounter the term "pound" or the symbol "lb" in a random quote, you cannot know whether the author had paired it with poundal or slug or whether they were using it interchangeably for a unit of mass or force.
Which "paper by Comings" do you mean? We can reinstate the Lindeburg citation, but I don't have access to it, so can't check what it actually has to say on the matter. The other reference was rubbish by Wikipedia's standards.
Another point is that there are different valid approaches, but they may require alterations (i.e. mostly constant factors) to familiar formulas.
A minor point of the table is that the metric system also has had such variants.

That mass and force have different units should not be hidden. Force equation is also wrong; subscript on g should be dropped or w should be m.

Your comment on this Talk page starts with saying that the same unit can be used for mass and force (from weight), but in this edit summary you want to distinguish them. Weight is the base dimension in the middle column, so w should be used in the formula.
Originally, the table used unit names instead of symbols, but the latter should make it more concise. — Christoph Päper 15:09, 11 October 2017 (UTC)
Not concise at all. Just more confusing. It would be better to spell out the unit names in full. I would do that myself except lb and kg span two rows now so I can't. Can we go back to a version that had the option of distinguishing between a unit of weight and a unit of mass? Dondervogel 2 (talk) 22:09, 12 October 2017 (UTC)
There, I've changed the template to show unit names instead of symbols by default, except for the acceleration row.
As for the middle column group, what exactly do you all want and why? — Christoph Päper 13:29, 13 October 2017 (UTC)
Alternatives (without tooltip and without metric unit for A/B/C/D)
Current A B C D
Mass (m) pound kilogram pound pound-mass pound pound-mass
Force (F),
weight (w)
pound pound-force pound-force pound
Thank you for taking the trouble. My understanding is that "pound-force" and "(avoirdupois) pound" are the correct (internationally standardized) names for these units. For this reason my preference is C, especially if pound is linked to pound (avoirdupois). My second choice would be B. The others make my hair stand on end. Dondervogel 2 (talk) 15:29, 13 October 2017 (UTC)
That means you want to document how English legacy units are currently used when they are mixed with other systems, notably SI. That is a noble endeavor (e.g. done in ISO 80000-4 Annex B), but not at all the purpose of this template. (I would prefer B then, but could live with C.) The entries in this table show what is used within an environment that consistently uses the system of the respective column exclusively. If you would be working only with EE units (and luckily you'll never have to), you would not distinguish pound as a unit of mass or force.
In many other places on WP your critique may apply, but not in this particular case. — Christoph Päper 19:53, 14 October 2017 (UTC)
The middle column is a four-unit system in which both mass and force are base quantities and have different units. See the article English Engineering units and the article by Comings referenced there; see also the article by Klinkenberg at the same site. A three-unit system in which mass and force have the same unit is a different system. The equation in the middle column is false unless gc means simply g; it doesn't matter what the base dimensions are. (talk) 01:48, 15 October 2017 (UTC)
That paper from 1940 actually seems like a good reference for (and perhaps the original source of) this template, because it identifies the three approaches and labels them gravitational (or technical), engineering and absolute (or dynamical), respectively. I take it you, like Comings, would prefer option B above then.
Honestly, I've lost track whether gc was supposed to stand for standard gravitational acceleration g0 (9.80665 m/s²), local acceleration gL, some other g or the dimensional conversion factor β used by Comings.
The difference between this table in its current state and Comings' paper is indeed, like you say, that the latter identifies an additional fourth primary dimension (i.e. mass and force) where the former still assumes a single one (i.e. weight) as in the other columns. I don't think it's really a different system, though. — Christoph Päper 21:59, 15 October 2017 (UTC)
In all systems, F = ma/gc = wa/g, where gc = 32.174 lb·ft/lbf·s2, g is the actual acceleration due to gravity, and w is the actual weight of a body. In EE gc and g have different dimensions. If lbf = lb, then gc = g0, the standard acceleration due to gravity. But this is still not the same as g, and the equation F = wa/g0 is incorrect unless w means standard weight. See the article Standard gravity. Often, the hardest things to understand in science and mathematics are the trivial things. (talk) 05:49, 16 October 2017 (UTC)


  1. ^ Comings, E. W. (1940). "English Engineering Units and Their Dimensions". Industrial & Engineering Chemistry. 32 (7): 984–987. doi:10.1021/ie50367a028.
  2. ^ Klinkenberg, Adrian (1969). "The American Engineering System of Units and Its Dimensional Constant gc". Industrial & Engineering Chemistry. 61 (4): 53–59. doi:10.1021/ie50712a010.
  3. ^ IEEE Std 260.1™-2004, IEEE Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch-Pound Units, and Certain Other Units)


I was reading the article Slug (unit) which uses this template and was confused between the different systems which just use abbreviations to identify them. Initially I went to edit Slug, but then realised that this template existed. I've added an explanatory column to the documentation but wonder if the expanded names could be incorporated as a footnote (possibly optional) to the main output? Regards, Martin of Sheffield (talk) 10:06, 22 September 2018 (UTC)