Measurement Converter

Metric, imperial and US measures

The UK uses metric units for most things but still talks in miles, pints and stones, while American recipes and products use US customary units. Some names are shared but the sizes aren’t: a US pint, gallon or fluid ounce is different from the UK one. The converter keeps them separate so you always know which you’re getting.

Results are shown to 7 significant figures with trailing zeros removed. The conversion factors are the official definitions, so length, weight, volume and area results are exact to that precision.

Length and distance

One inch is exactly 2.54 cm, one foot is 12 inches (30.48 cm), and one mile is 1,760 yards or about 1.61 km.

1 in = 2.54 cm
1 ft = 0.3048 m
1 mile = 1.609344 km
5 km = 3.106856 miles

Weight

In the UK, body weight is often given in stones and pounds. One stone is 14 pounds, and one pound is 453.59237 grams.

1 kg = 2.204623 lb
1 st = 6.350293 kg
1 oz = 28.34952 g
100 g = 3.527396 oz

Volume: UK and US measures

Measure	UK	US
Teaspoon	5 ml	4.928922 ml
Tablespoon	15 ml	14.78676 ml
Cup	250 ml	236.5882 ml
Fluid ounce	28.41306 ml	29.57353 ml
Pint	568.2613 ml	473.1765 ml
Gallon	4.54609 litres	3.785412 litres

UK spoons and cups are the metric measures used in modern UK recipes and measuring sets.

Grams to cups for baking

Cups measure volume, so how many grams fit in one depends on the ingredient – a cup of sugar weighs over half as much again as a cup of flour. Choose “Cooking” above and pick an ingredient to convert between weight and volume. These are averages: how you fill the cup makes a difference, so use scales when accuracy matters.

Ingredient	1 US cup	100 g
Plain flour	about 120 g	0.8333333 US cups
Caster sugar	about 190 g	0.5263158 US cups
Granulated sugar	about 198 g	0.5050505 US cups
Butter	about 227 g	0.4405286 US cups
Rice (long-grain, uncooked)	about 198 g	0.5050505 US cups
Water	about 236.5882 g	0.4226753 US cups
Self-raising flour	about 113 g	0.8849558 US cups
Strong white bread flour	about 120 g	0.8333333 US cups
Wholemeal flour	about 113 g	0.8849558 US cups
Cornflour	about 112 g	0.8928571 US cups
Ground almonds	about 96 g	1.041667 US cups
Cocoa powder	about 84 g	1.190476 US cups
Icing sugar	about 113 g	0.8849558 US cups
Light brown sugar	about 213 g	0.4694836 US cups
Honey	about 336 g	0.297619 US cups
Maple syrup	about 312 g	0.3205128 US cups
Milk	about 227 g	0.4405286 US cups
Double cream	about 227 g	0.4405286 US cups
Yoghurt	about 227 g	0.4405286 US cups
Vegetable oil	about 198 g	0.5050505 US cups
Peanut butter	about 270 g	0.3703704 US cups
Rolled oats	about 89 g	1.123596 US cups
Chocolate chips	about 170 g	0.5882353 US cups
Raisins	about 170 g	0.5882353 US cups
Cheddar (grated)	about 113 g	0.8849558 US cups
Salt (table)	about 288 g	0.3472222 US cups
Baking powder	about 192 g	0.5208333 US cups
Bicarbonate of soda	about 288 g	0.3472222 US cups

Weights per cup from King Arthur Baking’s ingredient weight chart (flour spooned and levelled). Water is 1 g per ml.

Temperature

Temperature scales don’t just multiply – they start from different zero points. To go from Celsius to Fahrenheit, multiply by 9/5 and add 32; to go back, subtract 32 and multiply by 5/9. Kelvin starts at absolute zero, −273.15 °C. Negative temperatures work as normal.

0 °C = 32 °F (water freezes)
37 °C = 98.6 °F (body temperature)
180 °C = 356 °F (moderate oven)
-40 °C = -40 °F (where the scales meet)

Area

Floor space is often quoted in square feet and land in acres or hectares. Remember that area units scale by the square: a square metre is 10.76 square feet, not 3.28.

1 m² = 10.76391 sq ft
1 acre = 4,046.856 m²
1 ha = 2.471054 acres

Working out a discount or a price per square metre? Try the percentage calculator or the VAT calculator.

Speed, fuel, data and engineering units

Fuel economy is the one conversion that isn’t a simple multiplication: litres per 100 km measures fuel used, while miles per gallon measures distance travelled, so one goes up as the other goes down. UK mpg uses the larger 4.546-litre imperial gallon, so the same car shows a higher figure in UK mpg than in US mpg.

Data sizes come in two families. kB, MB, GB and TB step up in thousands (as drive makers and broadband providers use), while KiB, MiB and GiB step up in multiples of 1,024 (as many operating systems report). Broadband speeds are in megabits per second: divide by 8 for megabytes per second.

70 mph = 112.6541 km/h
50 mpg (UK) = 5.649619 l/100 km
100 Mbps = 12.5 MB/s
1 TB = 931.3226 GiB
1 bar = 14.50377 psi
100 kW = 134.1022 hp
1 kWh = 3.6 MJ

Horsepower is the imperial (mechanical) horsepower used for UK and US cars; European specs often quote metric horsepower (PS), which is about 1.4% smaller. Calories are thermochemical calories: a food “Calorie” is a kilocalorie.

Frequently asked questions

How many centimetres are in an inch?

Exactly 2.54. The inch has been defined as 25.4 mm since 1959, so 1 in = 2.54 cm and 1 cm = 0.3937008 in.

How do I convert stone to kilograms?

One stone is 14 pounds, which is 6.35029318 kg. Multiply stone by 6.35 for a quick answer: for example, 11 st = 69.85322 kg.

Is a UK pint the same as a US pint?

No. A UK (imperial) pint is 568 ml and a US pint is 473 ml, about 20% smaller. UK and US gallons and fluid ounces differ too, so choose the right one for your recipe or label.

How many grams are in a cup?

It depends on the ingredient, because a cup measures volume, not weight. A US cup of plain flour weighs about 120 g, but a cup of granulated sugar is about 198 g and a cup of water 237 g. Choose “Cooking” and pick your ingredient for a closer answer.

What’s the difference between a UK cup and a US cup?

Modern UK recipes use a 250 ml metric cup, while US recipes use a 236.6 ml cup. UK teaspoons and tablespoons are 5 ml and 15 ml; US ones are very slightly smaller.

How do I convert Celsius to Fahrenheit?

Multiply by 9, divide by 5, then add 32. For example, 20 °C = 68 °F and 180 °C = 356 °F (a typical oven temperature).

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