Metrication in Ireland

Metrication in the Republic of Ireland happened mostly in the 20th century and was officially completed in 2005, with a few exceptions.

Information sign about the speed limit units used in Ireland

The island of Ireland gradually adopted the British imperial measurement system, fully replacing traditional Irish measure during the 19th century, and these units continued to be used after the independence of the Irish Free State (1922) and the establishment of the Republic of Ireland (1937/49). The Irish Free State joined the Metre Convention in 1925. In 1980 the European Union asked all of its member states to convert to the metric system, and in Ireland and the UK this process was originally to have been completed by 2009.[1] Metrication succeeded in Ireland with the changeover fully completed in 2005, with some exceptions.


During the First World War and after the Easter Rising, Charles A Stanuell, former President of the Statistical and Social Inquiry Society of Ireland, published a paper advocating the use of the metric system and a decimal currency in the UK, of which Ireland was then a part.[2]

Metrication in Ireland began in the 1970s and by 2005 was completed, with the main exception being that the imperial pint (568 ml) is still used in eateries and pubs for reasons of tradition. The phrase a "glass of beer" is a colloquial expression for a half-pint (284 ml).[3] All other loose goods sold by volume must be sold using metric units.[4]

Distance signs had displayed kilometres since the 1970s but road speed limits were in miles per hour until January 2005, when they were changed to kilometres per hour.[5] Since 2005 all new cars sold in Ireland have speedometers that display only kilometres per hour; odometers generally became metric as well.

The metric system is the only system taught in schools. Beginning in 1970, textbooks were changed to metric. Goods in shops are labelled in metric units.

Continuation of supplementary Imperial unitsEdit

In 2006 it became apparent that the 2009 cut-off for the use of Imperial supplementary units could cause problems in US-EU trade. After consultation, EU Directive 2009/3/EC of 11 March 2009, among other measures, permitted:[6]

  • The indefinite use of Imperial supplementary indications.
  • The United Kingdom and Ireland to continue the limited exemptions concerning specified uses of the pint, mile and troy ounce, considering the absence of any impact of these exemptions on cross-border trade and the principle of subsidiarity; whilst repealing the exemption for the use of acres for land registration which is no longer applied.

These amendments were published on 7 May 2009 and became effective on 1 January 2010.

Exceptions to Irish metricationEdit

Legal weights and measures for tradeEdit

Packaged goodsEdit

  • The vast majority of packaged butter sold at Ireland's top three supermarkets come in 8- and 16-ounce sizes, but are labelled as 227 g and 454 g respectively.[7][8][9]
  • Milk cartons served at schools are 13 imperial pint (189 ml) in volume, despite packaged milk sold at supermarkets coming in metric quantities.[10]


  • Horse racing in Ireland continues to use stones, pounds, miles and furlongs as measurements.[11]
  • While roads in Ireland measure distances in metres and kilometres and speed limits in kilometres per hour, the railway network operates on imperial measurements such as distances in miles and speeds in miles per hour.[12][13]
  • Display sizes for screens on television sets and computer monitors have their diagonal measured in inches.
  • While petrol and diesel fuel are sold by the litre, barrels of oil are measured by multiples of the imperial gallon.
  • Some golf courses are measured in metres while others are measured in yards.[14]
  • Tyre pressure is measured in pounds per square inch (PSI).
  • Like in most countries, aviation (altitude and flight level) is measured in feet.

References in Oireachtas debatesEdit

See alsoEdit



  1. ^[bare URL]
  2. ^ Stanuell, Charles A. (1915–1917). "Weights and measures after the war" (PDF). Journal of the Statistical and Social Inquiry Society of Ireland. Dublin. XCVI (XIII): 460–473.
  3. ^ "'Morning After' Campaign". Mature Enjoyment of Alcohol in Society. Retrieved 14 January 2014.
  4. ^ a b c Book (eISB), electronic Irish Statute. "electronic Irish Statute Book (eISB)". Retrieved 21 February 2021.
  5. ^ Book (eISB), electronic Irish Statute. "electronic Irish Statute Book (eISB)". Retrieved 21 February 2021.
  6. ^ "Directive 2009/3/EC of the European Parliament and of the Council of 11 March 2009 amending Council Directive 80/181/EEC on the approximation of the laws of the Member States relating to units of measurement". Retrieved 8 May 2009.
  7. ^ "Ireland: Grocery market share 2019". Statista. Retrieved 21 February 2021.
  8. ^ "SuperValu Ireland Butter". Retrieved 21 February 2021.
  9. ^ "Tesco Ireland Butter". Retrieved 21 February 2021.
  10. ^ Coyle, Colin. "Schools cry over free spilt milk". ISSN 0140-0460. Retrieved 21 February 2021.
  11. ^[bare URL]
  12. ^ "Republic of Ireland". Retrieved 22 February 2021.
  13. ^ Rail, Irish. "Network Statement". Irish Rail. Retrieved 22 February 2021.
  14. ^ "Golf Europe: Golf tours and travel in Ireland: Frequently asked questions".