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Metrication in Canada

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Metrication in Canada

The metrication logo used in Canada during the 1970s and 1980s.

Metrication in Canada began in 1970 and while Canada has converted to the metric system for many purposes, there is still significant use of non-metric units and standards in many sectors of the Canadian economy. This is mainly due to historical ties with the United Kingdom (before metrication), the traditional use of the imperial system of measurement in Canada, close proximity to the United States, and to public opposition to metrication during the transition period.[1][2]


  • Before conversion 1
  • Conversion process 2
    • The changeover 2.1
    • Metrication stalled 2.2
  • Common usage today 3
    • Daily usage 3.1
    • Experience 3.2
    • Temperature 3.3
    • Products and retail 3.4
    • Commercial usage 3.5
    • Agriculture 3.6
    • Health care 3.7
    • Engineering 3.8
    • Trades 3.9
    • Firearms 3.10
    • Print 3.11
    • Air transportation 3.12
  • Education regarding the imperial system 4
  • See also 5
  • References 6
  • External links 7

Before conversion

Until the 1970s, Canada traditionally used the Imperial measurement system, labelled as "Canadian units of measurements" under Schedule II, Section 4 of the Weights and Measures Act (R.S., 1985, c. W-6).[3] These units have the same name and, with the exception of capacity measures such as the gallon, the same values as US customary units. For example, before metrication in Canada, gasoline was sold by the imperial gallon (about 4.55 litres). In cross-border transactions, it was often confusing whether values quoted in pints, gallons, tons, etc. were referring to the US values (3.75 litres) or the imperial values of these units.

Conversion process

The Liberal federal government of Pierre Trudeau first began implementing metrication in Canada in 1970 with a government agency dedicated to implementing the project, the Metric Commission, being established in 1971. By the mid-1970s, metric product labelling was introduced. In 1972, the provinces agreed to make all road signs metric by 1977. There was some resistance to metrication, especially as the sectors of the economy where the federal Weights and Measures Act required metric to be used grew in number. The metrication of gasoline and diesel fuel sales in 1979 prompted 37 Progressive Conservative Members of Parliament to open a "freedom to measure" gas station in Carleton Place, Ontario, selling gas in both imperial gallons and litres. The city of Peterborough, Ontario, was a noted hotbed of opposition to metrication, having been one of the government's three test centres for the metrication process. Bill Domm, a Member of Parliament representing the riding of Peterborough, was one of the country's most outspoken opponents of metrication. During this period, a few government employees lost their jobs for their opposition to metrication.[4] One official with Revenue Canada who publicly opposed mandatory metric conversion was dismissed for "conduct unacceptable for a public servant."

The changeover

A long-ago metricated speed-limit sign in Bolton, Ontario, with the old "25 mph" value now showing through

Since 1976 the law requires that all prepackaged food products must declare their mass or their volume in metric units, though Canadian imperial units are still legally permitted on packaging.[5] Milk has been thoroughly metric since 1980. In April 1975 Fahrenheit temperatures were replaced by Celsius. In September 1975 rainfall was first measured in millimetres and snow in centimetres. Since April 1976, wind speed, visibility, and atmospheric pressure have been in SI units, with the pressure in kilopascals. In September 1977 every speed-limit sign in the country was changed from miles per hour to kilometres per hour.[6]

Metrication stalled

The election of the Progressive Conservative government of Brian Mulroney in 1984 resulted in the abolition of the Metric Commission on March 31, 1985. This ended the process of affirmative metrication in Canada, and some regulations requiring metric measurements have either been repealed or are no longer enforced.

Training on metric conversion was not universal. Poor metrication training was a contributing factor to Air Canada Flight 143, the so-called Gimli Glider, running out of fuel mid-flight on 23 July 1983.

Notwithstanding the end of officially sanctioned metrication in Canada, most laws, regulations, and official forms exclusively use metric measurements. However, imperial measures still have legal definitions in Canada and can be used alongside of metric units.[3][7][8]

Common usage today

Daily usage

Canadians typically discuss the weather in degrees Celsius, purchase gasoline in litres, observe speed limits set in kilometres per hour (km/h), and read road signs and maps displaying distances in kilometres. Cars have metric speedometers and odometers, although many speedometers include smaller figures in miles per hour (mph). Fuel efficiency for new vehicles is published by Natural Resources Canada in litres per 100 kilometres and miles per gallon.[9] Window stickers in dealer showrooms often include "miles per gallon" conversions. The railways of Canada continue to measure their trackage in miles, and speed limits in mph. Canadian railcars show weight figures in both imperial and metric.

Today, Canadians typically use a mix of metric and imperial measurements in their daily lives. However the use of the metric and imperial systems varies according to generations. Newborns are measured in SI at hospitals, but the birth weight and length is also announced to family and friends in imperial units. Among the broader population, imperial units are often used to indicate height and weight.[10] However, Canadian driver's licences give height in centimetres.[11][12] In addition, Fahrenheit is often used for cooking, as are imperial cooking measurements, although some appliances in Canada are labelled with degrees Celsius or are convertible, and metric cooking measures are widely available; imperial temperatures are also often used outside of the kitchen, such as when measuring the water temperature in a pool. Stationery and photographic prints are also sold in sizes based on inches and the most popular paper sizes, letter and legal, are sized in imperial units. Canadian Football League games continue to be played on fields measured in yards; golfers also expect courses to be measured in yards.


The use of metric or imperial measurements varies by age and region. Canadians who have received only metric instruction in school (from the early 1970s) are more familiar with metric measurements. However unlike in the rest of Canada, metrication in the Francophone province of Quebec has been more implemented and metric measures are more consistently used in Quebec than elsewhere in Canada. The use of imperial units is more common in rural areas in the rest of the country, where opposition to metrication was strongest, rather than in urban areas.

Canadians are exposed to both metric and imperial units, and it is not unusual for there to be references to both metres and feet, acres and hectares, or grams and ounces, in the same conversation.


Despite the exclusive use of degrees Celsius in weather reports, some older Canadians still use Fahrenheit. Most outdoor thermometers display temperatures in both Fahrenheit and Celsius. Additionally, outdoor signs usually display Celsius with occasional reference to Fahrenheit. Inside newer buildings, digital and analog thermostats display temperature settings in degrees Celsius or Fahrenheit. Environment Canada still offers an imperial unit option beside metric units[13] and some radio stations near the United States border (such as CIMX-FM and CIDR-FM) primarily use imperial units to report the weather. Canadian ovens are almost always set using the Fahrenheit scale.[14]

Products and retail

Many food and retail products are sold according to metric units, though this is not always the case. The price of a piece of meat, for example, a steak, is typically advertised per pound, but the price printed on the package is per kilogram; the latter is calculated. The prices of fruits and vegetables are usually advertised in pounds, although the price per kilogram is also displayed, usually in smaller type. More expensive items such as deli, meats, and fish are often advertised per 100 grams. Many products are sold in imperial sizes, but labelled in metric units. An example of this is butter, which is sold in a 454-gram package (and labelled as such), even though it represents one pound (and in many cases is also labelled with the imperial unit.) This is known as "soft metric" (as opposed to a "hard metric" system, where packages and measures are generally sold in "round numbers"; in a hard metric system, butter might come in a 500 g package).

In restaurants, wine is usually served by the litre, bottle (750 mL (26 imp fl oz; 25 US fl oz)), 500 mL (18 imp fl oz; 17 US fl oz), but a wine glass is measured in ounces. Similarly, fast food restaurants (e.g. McDonald's Quarter Pounder) often advertise measurements of food and drink in US customary units, but converted to metric units, either because the containers are made to US standards, or the franchise is US-based and uses a standard size for its products. Thus in Canada a 20 US fluid ounce bottled soft drink is labelled as 591 mL. Beer in bottles continues to be 12 imperial fluid ounces (labelled as 341 mL), but beer in cans is filled to 12 US fluid ounces (labelled as 355 mL).[15] There is also a larger sized beer bottle which is labelled as containing 1,183 mL. This corresponds to exactly 40 US fluid ounces.[15] Some of these package sizes have been introduced since Canadian metrication began; for example, the traditional Canadian soft drink can was 10 imperial fluid ounces (284 mL), later marketed as 280 mL. Only in the early 1990s did the US-derived 355 mL size displace it. Television sets and computer screens are also measured in inches. Standard and special fasteners like alloys, nuts, bolts, washers, studs, tapping, self drilling screw and socket screware are often quoted in both imperial and metric, products range from 256 in (0.91 mm) diameter up to 4 in (100 mm).[16]

Commercial usage

Supermarkets will often advertise foods such as meats and produce "per pound", and small businesses are exempt from having metric scales and legally sell by the pound. While most supermarket scales display both metric and imperial units,[17] products advertised by the pound in a supermarket flyer are inevitably sold to the customer (at the point of sale) based on a price "per 100 grams" or "per kilogram".

Construction materials, including construction lumber and drywall, continue to be sold in imperial measurements; retrofitting metric-sized (designed for 400 millimetre centres) wallboard on old 16 in (410 mm) spaced studs is difficult. Construction of commercial and residential spaces are done using imperial units and advertised accordingly.[18][19] However, the zoning by-laws and building codes that govern construction are in metric, although most building codes will also contain imperial equivalents. In addition, rural areas in Western Canada (Canadian Prairies) were mapped and segmented using the Dominion Land Survey. This based most rural roads on a mile measurement which when viewed from the air has the appearance of a checkerboard or grid.[20] Because of this standard now etched into the landscape, it is still common to refer to distance in miles since counting the number of mile roads is easy. In contrast, in much of southern Ontario the basic survey grid was based on a mile-and-a-quarter (1.25 mi), which corresponds almost exactly to a 2 kilometre grid and which makes miles no more natural than kilometres. It should be noted that 11/4 mi is equal to 100 chains (10 furlongs) and it was that sized grid that was used in the original surveys and thus would have been more familiar.[21][22]

Free trade with the United States has resulted in continued exposure to the US system. Since the United States is Canada's largest trading partner and vice versa, Canadian exporters and importers must be accustomed to dealing in US customary units as well as metric.


Canada uses an Avery or imperial bushel (36.369 litres) when selling oats, wheat, and other grains. When dealing with the US oat markets though, special attention must be paid to the definition of bushel weight because US uses a Winchester bushel (35.239 litres).[23] In livestock auction markets, cattle are sold in dollars per hundredweight (short), whereas hogs are sold in dollars per hundred kilograms.

Health care

In the health care system, SI units are often given precedence (for example, for measurements of blood cholesterol, the units are millimole per litre, whereas they are milligram per decilitre in the United States). Most physicians chart patient height and weight in imperial units, and while most growth charts display both systems of measurement, the majority of hospitals officially document such parameters in metric.[24] Dieticians still use kilocalories, and doctors use millimetres of mercury.[6] While these units are technically metric, they are not SI units.


Because most fasteners, machine parts, pumps, piping, and all building materials are sold in imperial or US customary units, many mechanical and civil engineers in Canada mainly use imperial units.. On the other hand, many chemical, nuclear and electrical engineers and engineering physicists employ metric units. As in the United States, Canadian engineers are educated in both systems and are keenly aware of the differences between the imperial, metric and US customary systems.


Trades associated with machine work, such as machinists, automotive, and heavy duty technicians, frequently use both metric and imperial. Machines made in Canada often incorporate parts from other countries and thus the finished product may have both metric and imperial parts. Farm and industrial equipment manufactured in Canada will most often use imperial fasteners and structural steel, but fluid capacities are always listed in metric.

Building trades such as plumbing and carpentry often use imperial units. Rough timber, drywall, plywood, fasteners, pipes, and tubing are all sold in imperial units. Nails in hardware stores are measured in inches but sold in metric weight packages.

Electricians in every country use metric units such as volts and amperes, but motors and engines are still quoted in horsepower (of which several definitions exist). Electric car motors are rated in kilowatts. However, Canada uses, among other things, the US American wire gauge standard instead of the square millimetre (mm2) used in the IEC 60228 standard of the International Electrotechnical Commission, although the Canadian Electrical Code includes both in its regulations. For example, the usage of either 14 AWG or 2.5 mm size wire for a given circuit would be acceptable. Conduit sizes are in inch diameters, although some manufacturers include the metric size printed on the conduits (for example, 12 in (13 mm), 58 in (16 mm), 34 in (19 mm).


Imperial units also remain in common use in firearms and ammunition. Imperial measures are still used in the description of cartridge types, even when the cartridge is of relatively recent invention (e.g. 0.204 Ruger, 0.17 HMR, where the calibre is expressed in decimal fractions of an inch). However, ammunition which is classified in metric already is still kept metric (e.g. 9 mm, 7.62 mm). In the manufacture of ammunition, bullet and powder weights are expressed in terms of grains for both metric and imperial cartridges.


Canada uses the inch-based paper standard e.g. the US Letter, rather than the metric-based A4 paper size used throughout most of the world. The government, however, uses a combination of ISO paper sizes, and CAN 2-9.60M "Paper Sizes for Correspondence" specifies P1 through P6 paper sizes, which are the US paper sizes rounded to the nearest 5 mm.[25][26]

Air transportation

Luggage restrictions and limits at Canadian airports are in metric values with soft imperial conversion values.[27] Runway lengths are given in feet and speed in knots[28][29] as is the US. Like a number of metric countries altitude is given in feet.[30][31]

Fuel is nowadays measured in metric units. The Gimli Glider incident is a famous case of a kilogram-pound mistake during which, the miscalculation of the amount of fuel in an Air Canada airplane with a malfunctioning fuel gauge caused the plane to run out of fuel mid-flight.

Education regarding the imperial system

In 2005, the Ontario government announced changes to the secondary-school mathematics curriculum that would allow imperial units to be taught along with metric units.[32] This marked a departure from previous governments' efforts to make sure that the curriculum used only the metric system. This was done in light of the refusal or reluctance of much of the private sector to metricate; thus students had been leaving school unprepared for the units used in the workplace. Many other provinces and territories also include the imperial system of measurements as part of their educational curriculum.[33][34][35][36][37][38]

See also


  1. ^ Canadians rebel against metric system
  2. ^ A Canadian compromise between metric and imperial
  3. ^ a b "Weights and Measures Act: Canadian units of measure". Department of Justice. Retrieved 2007-11-14. 
  4. ^ "Fired for opposing metric". CBC. Retrieved 2008-03-11. 
  5. ^ Food Labelling for Industry
  6. ^ a b [2]
  7. ^ "Canadian Food Inspection Agency - Guide to Food Labelling and Advertising - Chapter 11". Canadian Government. Retrieved 2007-12-01. 
  8. ^ "Consumer Packaging and Labelling Regulations". Government of Canada, Department of Justice Canada, Legislative Services Branch. Retrieved 2007-12-01. 
  9. ^ "Fuel Consumption Ratings". Government of Canada. January 2011. Retrieved 2011-05-18. 
  10. ^ What's a healthy weight for you?
  11. ^ "New Driver's Licence and Identification Cards".  
  12. ^ "Change information on a driver’s licence".  
  13. ^ Environment Canada weather in imperial units and Environment Canada weather in metric unsits
  14. ^ Pearlstein, Steven (2000-06-04). "Did Canada go metric? Yes - and no". The Seattle Times. 
  15. ^ a b "The Beer Store Price list CANADIAN". The Beer Store. Retrieved 2008-03-11. 
  16. ^ "Metric Fasteners companies - Displaying all 17". Canadian Trade Index. Archived from the original on 2015-06-01. 
  17. ^ Legal for Trade - Canada
  18. ^ Commercial Services
  19. ^ Canadian Home Designs
  20. ^ Google Maps view of southwestern Manitoba, near Brandon
  21. ^ The Improtance of Title Searches
  22. ^ Land Titles vs. Land Registry
  23. ^ Marketing Oats in Canada
  24. ^ Is My Child Growing Well?
  25. ^ Kuhn, Markus. "International standard paper sizes". Retrieved 2008-03-06. 
  26. ^ "Canadian standard CAN 2-9.60M paper sizes"
  27. ^ Carry-On Baggage
  28. ^ Canada Flight Supplement. Effective 0901Z 24 July 2014 to 0901Z 18 September 2014
  29. ^ 1.8. Units of Measure
  30. ^ A Common European Transition Altitude
  31. ^ Aeronautical Information Publication at EuroControl Basic Log-in (free registration required).
  32. ^ "The Ontario curriculum Grades 9 and 10 2005 REVISED Mathematics". Ontario Ministry of Education. 2005. Retrieved 2007-12-03. 
  33. ^ "Outcomes with Assessment Standards for Applied Mathematics 10" (pdf). Alberta Education/Alberta Learning, Alberta, Canada. August 2002. Retrieved 2007-12-10. 
  34. ^ "Nova Scotia Student: LifeWork Portfolio. A teaching resource" (PDF). Nova Scotia Department of Education. Province of Nova Scotia. 2005. Retrieved 2007-12-10. 
  35. ^ "Essentials of Mathematics 11 -Measurement Technology". British Columbia Ministry of Education. November 22, 2000. Retrieved 2007-12-10. 
  36. ^ "Key Concepts in the Curriculum" (PDF). British Columbia Ministry of Education. February 2006. Retrieved 2007-12-10. 
  37. ^ "Curriculum". Government of Yukon. 2007-11-22. Retrieved 2007-12-18. 
  38. ^ "Senior 3 Consumer Mathematics (30S) Outcomes by Unit". Manitoba Department of Education, Citizenship and Youth. Archived from the original on 2007-08-18. Retrieved 2007-12-10. 

External links

  • (R.S., 1985, c. W-6) Re-accessdate = 2011-08-04Weights and Measures ActCanadian
  • For Good Measure: Canada Converts to Metric at CBC Digital Archives
  • CIA World Factbook: Weights & Measures
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