Units by Country: Which Measurement System Does Each Region Use?
See what people actually use day to day, and convert the numbers quickly when you cross borders.
Measurements differ by country because standards evolved locally long before global trade and modern science pushed people toward shared systems. Today, the United States, Myanmar, and Liberia have not officially adopted the metric system. Most countries use SI units, but many kept a few legacy units for daily life after going metric.
These differences matter when you travel, shop online, or work across borders. You might read road signs in miles, buy clothes in unfamiliar size systems, or follow a recipe written in grams, cups, or ounces. They also affect medical records, sports stats, and product labels where precision and context both matter.
This guide focuses on common everyday units, not every legal or scientific standard. When you need exact math, use the full unit converter to calculate any value quickly.
The Big Picture: Metric vs Imperial
Most places use metric for official and everyday units. The confusing part is where a country goes metric on paper, but keeps older units for roads, people's height, or drinks.
Group A: Metric onlyGroup B: Mixed in daily lifeGroup C: Imperial dominant
Group A
Most of EuropeChinaJapanSouth KoreaBrazilMost of AfricaMost of Southeast AsiaRussiaCentral Asia
Group B
United KingdomCanadaAustraliaIrelandIndiaSouth Africa
Group C
United States
Region by Region Breakdown
These sections focus on the units people see on signs, labels, and everyday conversations. Use the linked converters when you need exact conversions.
United States
The US uses the imperial system for almost everything in daily life.
Category
US unit
Metric equivalent
US or imperial notes
Distance
Miles
1 mi = 1.609 km
Road signs and travel
Short distance
Feet / inches
1 ft = 30.48 cm
Height and construction
Body weight
Pounds (lbs)
1 lb = 0.453 kg
Common for people
Cooking volume
Cups / fl oz
1 cup = 236.6 mL
Recipe volumes
Temperature
Fahrenheit
°F = (°C × 9/5) + 32
Weather and ovens
Fuel economy
Miles per gallon
1 mpg = 0.425 km/L
Compare carefully overseas
Liquid volume
US gallons
1 US gal = 3.785 L
Different from UK gallon
Area
Acres
1 acre = 0.405 hectares
Real estate and farming
Speed
mph
1 mph = 1.609 km/h
Road speed limits
Paper size
Letter (8.5×11 in)
≈ A4 (210×297 mm)
Printing across borders
Quirks
Shoe sizes use a different scale from UK and EU sizes.
Clothing sizes (S/M/L/XL) differ from EU numeric sizing.
US pints and gallons are smaller than UK pints and gallons.
Dates are written MM/DD/YYYY while most countries use DD/MM/YYYY.
US uses comma for thousands and period for decimals (1,000.50). Many European countries flip that (1.000,50).
UK mpg uses a larger gallon, so a UK car showing 50 mpg is not the same as a US car showing 50 mpg. Convert with: UK mpg × 0.8326 = US mpg.
Future tool: A dedicated fuel economy converter page would help here.
Australian or Canadian Cup vs US Cup
AU cup = 250 mL | US cup = 236.6 mL
Difference: about 1 tablespoon per cup. It adds up in baking when you scale a recipe. This affects cooks and recipe writers across English speaking countries.
Stones are common in UK and Ireland health and fitness, but almost nowhere else uses them. Convert carefully when comparing body weight across countries.
This inversion causes bad comparisons in car reviews. Use: mpg (US) = 235.2 / L/100km. The mini converter below handles both directions.
Clothing and shoe sizes
Sizes vary by brand, but these tables give a useful starting point. For online orders, always confirm the garment measurements.
Date format differences
US: MM/DD/YYYY | Most countries: DD/MM/YYYY
01/04/2025 means January 4 in the US, but April 1 in much of the world. ISO format (YYYY-MM-DD) avoids confusion on contracts, expiry dates, and schedules.
Paper sizes
Letter: 8.5×11 in | A4: 210×297 mm
A4 is slightly taller and narrower than US Letter. This affects printing, scanners, and document templates when you move files across borders.
In daily life, the United States relies on imperial units for distance, weight, and temperature. The UK and Canada use metric officially but still use imperial in specific places like road miles, feet and inches, and construction sizes. Most other countries use metric on signs, labels, and official documents.
The UK is officially metric, so most packaged goods use grams, kilograms, and litres. Roads still use miles and mph, many people use feet and inches for height, and pubs serve beer in pints. If you compare UK and US numbers, remember that the UK gallon and pint are larger.
Australia uses metric in everyday life, including kilometres, kilograms, and Celsius. A few legacy habits remain. Screen sizes and some tyre sizing still use inches, and many recipes assume an Australian metric cup that equals 250 mL. Use a volume converter when you bake across countries.
UK road distances use miles. Multiply miles by 1.609 to get kilometres. For quick checks, 10 miles is about 16.1 km and 60 mph is about 96.6 km/h. For accurate planning, use a miles to kilometres converter so you do not rely on rough estimates.
A stone is a UK and Irish body weight unit. 1 stone equals 14 pounds, which equals 6.35 kilograms. If someone gives a weight like 11 stone 4 pounds, convert stones to pounds, add the extra pounds, then convert the total to kilograms. This avoids rounding errors.
The UK uses the imperial system for pints, while the US uses a different gallon definition. A US pint is 473 mL, while a UK pint is 568 mL. That is about 20 percent more liquid in a UK pint, which matters for recipes, drink servings, and product comparisons.
EU sizes are usually numeric, while US sizing uses a different numeric scale and letter sizes like S and M. There is no universal mapping because brands cut garments differently. Use a reference chart as a starting point, then confirm with the brand's measurement table in centimetres or inches.
L/100km means litres used to drive 100 kilometres, and lower numbers are better. To convert to US mpg, use mpg (US) = 235.2 divided by L/100km. For UK mpg, use 282.5 divided by L/100km. This helps when you compare European and North American fuel economy.
Canada uses Celsius for weather and official reporting, including forecasts and body temperature. You may still see Fahrenheit on some older appliances and in US media. Canada also mixes systems in daily life, with many people using feet and inches for height and pounds for weight.
India uses metric officially for distance, weight, and temperature. Everyday life also includes local conventions. Financial reporting uses lakh and crore, and land area may use state specific units like bigha that vary widely. For travel and shopping, you will mostly see kilometres, kilograms, and Celsius.