A per mille (from Latin per mīlle, "in each thousand"), also spelled per mil, per mill, permil, permill, or permille is a sign indicating parts per thousand. Per mil should not be confused with parts per million (ppm).
The sign is written ‰, which looks like a percent sign (%) with an extra zero in the divisor. It is included in the General Punctuation block of Unicode characters: U+2030 ‰ PER MILLE SIGN (HTML
‰). It is accessible in Windows using
ALT+0137, and is accessible via a Compose Key using
The term occurs so rarely in English that major dictionaries do not agree on the spelling or pronunciation even within a single dialect of English and some major dictionaries such as Macmillan and Longman do not even contain an entry. The term is more common in other European languages where it is used in contexts, such as blood alcohol content, that are usually expressed as a percentage in English-speaking countries.
Examples of use include:
- Legal limits of blood-alcohol content for driving a road vehicle in some countries: for example: 0.6‰ or 0.2‰.
- Seawater salinity: for example: "the average salinity is 35‰".
- Tunnel and railway gradients (in some countries in Europe)
- Birth and death rates
- Baseball batting averages (colloquially)
- Property taxation rates: the millage rate (U.S.) or mill rate (Canada)
- Expressing stable-isotope ratios - for example: "δ13C was measured at −3.5‰"
- Expressing costs for print and online advertisements which are commonly sold at cost per mille (CPM); this is the common unit for all banner and display advertising
- Frequently used by email service providers to denominate the cost for 1,000 emails delivered as a cost per mille (CPM)
- Fineness of precious metals
- Cambridge Dictionary Online. "per mille". Cambridge University Press (Cambridge), 2014. Accessed 31 August 2012.
- Oxford Dictionaries: The British & World Dictionary. "per mille" Accessed 1 Aug 2014.
- Unicode. "General Punctuation". 2014. Accessed 5 Aug 2014.
- Oxford English Dictionary, 3rd ed. "per mil, adv." Oxford University Press (Oxford), 2005.
- eReference. "per mil Archived 2014-08-12 at the Wayback Machine". Houghton Mifflin. Accessed 31 Aug 2012.
- Oxford Dictionaries: The American Dictionary. "per mill". Accessed 1 Aug 2014.
- See entries above
- Macmillan Dictionary. "No result". Accessed 1 Aug 2014.
- Longman Dictionary of Contemporary English. "No result". Accessed 1 Aug 2014.