Metrication in Canada

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

Canada has converted to the metric system for many purposes but 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]


Before conversion

Until the 1970s, Canada traditionally used the imperial system of measurement units, labelled as "Canadian units of measurements" under Schedule II, Section 4 of the Weights and Measures Act (R.S., 1985, c. W-6).[2] These units have the same name and, with the exception of capacity measures such as the gallon, the same values as U.S. customary units. For example, before metrication in Canada, gasoline was sold by the imperial gallon (4.55 litres) whereas, south of the border in the U.S., it was sold by the U.S. gallon (3.78 litres). In cross-border transactions, it was often confusing whether values quoted in pints, gallons, tons, etc. were referring to the U.S. values 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 1981 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 small 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.[3] 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 prepacked food products must declare their mass or their volume in metric units. 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.[4]

Metrication stalled

After the election of Ronald Reagan in the United States, Congress closed the U.S. Metric Board, stalling metrication in the U.S. in the early 1980s (although upon leaving office in 1988, Reagan signed legislation declaring the metric system to be the nation's preferred system of measurement for trade and commerce). The election of the Progressive Conservative government of Brian Mulroney in 1984 similarly slowed, and ultimately stalled, metrication in Canada. The Metric Commission was abolished on March 31, 1985, and many regulations requiring metric measurements have either been repealed or are no longer enforced. As a result, Canadians today typically use a mix of metric and imperial measurements in their daily lives.

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.[citation needed] However, imperial measures still have legal definitions in Canada and can be used alongside of metric units.[2][5][6]

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.[7] 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.

Canadians, today 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. The older generations mostly uses the imperial system, while the younger generations uses the metric system more frequently. Newborns are measured in SI at hospitals, but the birth weight and length is also announced to family and friends in imperial units. Although drivers' licences in some provinces like British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, and Newfoundland and Labrador use SI units, other provinces use imperial units. 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. 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. Though traditional units are commonly used for height and weight, and are often used for length, a general understanding of traditional units does not generally go much beyond that unless perhaps the user has spent a significant amount of time in the United States.[citation needed] 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.[citation needed]

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, and grams and ounces in the same conversation.


Despite the virtually exclusive use of degrees Celsius in weather reports, some older Canadians still use Fahrenheit, often referring to it as "the old system". Most outdoor thermometers display temperatures in both Fahrenheit and Celsius. In addition, outdoor electronic signs tend to give both scales—in the format "68°/20C". Inside newer buildings, digital and analog thermostats usually display temperature settings in degrees Celsius, however Fahrenheit thermostats are still in use. Environment Canada still offers an Imperial unit option beside metric units, even though weather is typically measured and reported in metric units in the Canadian media. However, some radio stations near the United States border (such as CIMX-FM and CIDR-FM) primarily use imperial units to report the weather.[citation needed]

Products and retail

Most food and many retail products are sold according to metric units, though this is not always the case. Canadians will usually purchase their deli meats by the gram, but holiday turkeys, for example, are almost always purchased by the pound. Fruits and vegetables are almost exclusively sold in pounds, while more expensive items such as fish are often advertised in per hundred 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, even numbers; in a hard metric system, butter would come in a 500 g package).[citation needed]

In restaurants, wine is usually served by the litre, bottle (750 mL), half-litre and wineglass—measured in ounces. Similarly, fast-food restaurants (e.g. McDonald's Quarter Pounder) often advertise measurements of food and drink in U.S. customary units, but converted to metric units, either because the containers are made to U.S. standards, or the franchise is U.S.-based and uses a standard size for its products. Thus in Canada a 20 U.S. 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 U.S. fluid ounces (labelled as 355 mL).[8] There is also a larger sized beer bottle which is labelled as containing 1,183 mL. This corresponds to exactly 40 U.S. fluid ounces.[8] 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 1980s did the U.S.-derived 355 mL size displace it. Television sets are also measured in inches. Standard and special fasteners like alloys, nuts, bolts, washers, studs, tapping, self drilling screw & socket screware are quoted in often in both imperial and metric, products range from 256 in (0.91 mm) diameter up to 4 inch (101.6mm).[9]

Commercial usage

Supermarkets will often advertise foods such as meats and produce "per pound", since such prices may appear lower to consumers than prices advertised by kilogram. However, virtually all supermarket scales are metric, and the products advertised by the pound in a supermarket flyer are inevitably weighed and sold to the customer in the store based on a price "per 100 grams" or "per kilogram". Small businesses are exempt from having metric scales and legally sell by the pound.

Similarly, residential floor space is usually measured in square feet, as a 1,500-square-foot (139 m2) house may be more appealing to a homebuyer than the same size house that is advertised as 139 square metres. 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-inch (406.4 mm) spaced studs is difficult. Construction of commercial space is done in square metres, but advertised in square footage. All commercial construction in Canada is measured in metric. Interestingly, however, the zoning by-laws and building codes that govern construction are in metric (as are virtually all official documents), although some building codes will also contain imperial equivalents. In addition, rural areas 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.Google Maps view of South Western Manitoba near Brandon 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.

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


Canada uses an Avery or imperial bushel (36.369 litres) when selling Oats, Wheat, and Grain. 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 liters)[10] In livestock auction markets, cattle are sold in dollars per hundredweight (short), whereas hogs are sold in dollars per hundred kilograms.[citation needed]

Health care

In the health care system, SI units dominate (for example, for measurements of blood cholesterol, the units are millimole per litre, whereas they are milligram per decilitre in the United States). Some physicians chart patient height and weight in either unit, depending on when they started practising, though most growth charts are provided in metric units and the majority of hospitals document such parameters in metric units, but dieticians still use kilocalories, and doctors use millimetres of mercury.[11] While these units are metric, they are not SI units.


Because most fasteners, machine parts, pumps, piping, and all building materials are sold in imperial or U.S. customary units, many mechanical and civil engineers in Canada mainly use imperial units.[citation needed]. 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 U.S. 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 U.S. 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 inch (13 mm), 58 inch (16 mm), 34 inch (20 mm), etc).


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.[citation needed]


Canada uses the inch-based US Letter paper standard, rather than the metric-based A4 paper size used throughout most of the world.

Air transportation

Luggage restrictions and limits at Canadian airports are in imperial values with soft metric conversion values.[12] Altitude is measured in feet, and speed in knots.[13]


Reinstatement of 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.[14] 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.[15][16][17][18][19][20]

See also


  1. ^ Full-scale metric rebellion
  2. ^ a b "Weights and Measures Act: Canadian units of measure". Department of Justice. Retrieved 2007-11-14. 
  3. ^ "Fired for opposing metric". CBC. Retrieved 2008-03-11. 
  4. ^
  5. ^ "Canadian Food Inspection Agency - Guide to Food Labelling and Advertising - Chapter 11". Canadian Government. Retrieved 2007-12-01. 
  6. ^ "Consumer Packaging and Labelling Regulations". Government of Canada, Department of Justice Canada, Legislative Services Branch. Retrieved 2007-12-01. 
  7. ^ "Fuel Consumption Ratings". Government of Canada. January 2011. Retrieved 2011-05-18. 
  8. ^ a b "The Beer Store Price list CANADIAN". The Beer Store. Retrieved 2008-03-11. 
  9. ^
  10. ^$department/deptdocs.nsf/all/sis10952
  11. ^
  12. ^
  13. ^
  14. ^ "The Ontario Curriculum Grades 9 and 10 2 0 0 5 R E V I S E D Mathematics". Ontario Ministry of Education. 2005. Retrieved 2007-12-03. 
  15. ^ "Outcomes with Assessment Standards for Applied Mathematics 10" (pdf). Alberta Education/Alberta Learning, Alberta, Canada. August 2002. Retrieved 2007-12-10. 
  16. ^ "Nova Scotia Student: LifeWork Portfolio. A teaching resource" (PDF). Nova Scotia Department of Education. Province of Nova Scotia. 2005. Retrieved 2007-12-10. 
  17. ^ "Essentials of Mathematics 11 -Measurement Technology". British Columbia Ministry of Education. November 22, 2000. Retrieved 2007-12-10. 
  18. ^ "Key Concepts in the Curriculum" (PDF). British Columbia Ministry of Education. February 2006. Retrieved 2007-12-10. 
  19. ^ "Curriculum". Government of Yukon. 2007-11-22. Retrieved 2007-12-18. 
  20. ^ "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

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