Use the Common UK Measurement Conversions
Common UK measurement conversions usually involve moving between metric and imperial units. The maths is normally a simple conversion factor, but some categories, such as temperature, use a formula instead.
1 inch = 2.54cm, 1 mile = 1.609344km, 1kg ≈ 2.2046lb, 1 stone = 14lb, 1 UK pint ≈ 568ml, and °F = (°C × 9/5) + 32.
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Use the all-in-one converter for length, weight, temperature, volume and speed.
Length conversions used in the UK
Length conversions are common for height, furniture, property, screens, DIY, travel and road distances. The UK often mixes centimetres, metres, inches, feet, miles and kilometres depending on the situation.
| Conversion | Rule | Example |
|---|---|---|
| cm to inches | inches = cm ÷ 2.54 | 100cm ≈ 39.37in |
| inches to cm | cm = inches × 2.54 | 12in = 30.48cm |
| metres to feet | feet = metres × 3.28084 | 1.8m ≈ 5.91ft |
| feet to metres | metres = feet × 0.3048 | 6ft ≈ 1.83m |
| miles to km | km = miles × 1.609344 | 5 miles ≈ 8.05km |
| km to miles | miles = km ÷ 1.609344 | 10km ≈ 6.21 miles |
For more length units, use the length converter.
Weight conversions: kg, pounds and stone
Weight conversions are common for body weight, luggage, parcels, gym weights, food packs and product specifications. UK users often prefer body weight as stone and pounds, while metric weights are common on packaging and official documents.
| Conversion | Rule | Example |
|---|---|---|
| kg to lb | lb = kg × 2.2046226218 | 75kg ≈ 165.35lb |
| lb to kg | kg = lb ÷ 2.2046226218 | 150lb ≈ 68.04kg |
| lb to stone | stone = lb ÷ 14 | 168lb = 12 stone |
| stone to lb | lb = stone × 14 | 11 stone = 154lb |
| grams to ounces | oz = grams ÷ 28.3495 | 500g ≈ 17.64oz |
For stone-and-pounds style results, use the weight converter.
Volume conversions: ml, litres, pints and gallons
Volume conversions are useful for drinks, fuel, containers, recipes, watering, cleaning products and capacity checks. The UK pint and gallon are different from US versions, so it is important to choose the right one.
| Conversion | Rule | Example |
|---|---|---|
| litres to ml | ml = litres × 1,000 | 1.5L = 1,500ml |
| ml to litres | litres = ml ÷ 1,000 | 750ml = 0.75L |
| UK pints to litres | litres = pints × 0.568261 | 2 pints ≈ 1.14L |
| litres to UK pints | pints = litres × 1.759754 | 1L ≈ 1.76 UK pints |
| UK gallons to litres | litres = gallons × 4.54609 | 1 UK gallon ≈ 4.55L |
Temperature conversions: Celsius and Fahrenheit
Celsius is common in the UK for weather, homes and most modern ovens. Fahrenheit may appear in older recipes, international content or US product instructions. Temperature conversion is different because it uses an offset, not just a multiplier.
Fahrenheit = (Celsius × 9/5) + 32
Celsius = (Fahrenheit - 32) × 5/9| Celsius | Fahrenheit | Useful context |
|---|---|---|
| 0°C | 32°F | Freezing point of water |
| 10°C | 50°F | Cool day |
| 20°C | 68°F | Mild indoor temperature |
| 30°C | 86°F | Hot summer day |
| 100°C | 212°F | Boiling point of water at sea level |
Use the temperature converter for Celsius, Fahrenheit and Kelvin. For fan ovens and gas marks, use the oven temperature converter.
Speed conversions: mph, km/h and m/s
UK road speeds are normally given in miles per hour, but kilometres per hour are common abroad and metres per second may appear in science, engineering or weather contexts.
| Conversion | Rule | Example |
|---|---|---|
| mph to km/h | km/h = mph × 1.609344 | 70mph ≈ 112.65km/h |
| km/h to mph | mph = km/h ÷ 1.609344 | 100km/h ≈ 62.14mph |
| m/s to km/h | km/h = m/s × 3.6 | 10m/s = 36km/h |
| knots to mph | mph = knots × 1.150779 | 20 knots ≈ 23.02mph |
For road, travel and boating examples, use the speed converter.
How to round common UK conversions
Rounding depends on the purpose. A rough shopping or travel estimate can be rounded more freely than a DIY cut, parcel label, medication instruction or scientific measurement.
For more detail, read rounding converted measurements.
Common mistakes to avoid
- Confusing UK pints and gallons with US pints and gallons.
- Using decimal stone when stone and pounds would be clearer.
- Multiplying when the conversion should be divided.
- Rounding too early before a second calculation.
- Using a volume converter when the question is really about weight.
- Treating temperature like a normal multiplication-only conversion.
FAQs
What are the most common UK measurement conversions?
Common UK conversions include centimetres to inches, metres to feet, miles to kilometres, kilograms to pounds, kilograms to stone and pounds, litres to pints, mph to km/h and Celsius to Fahrenheit.
How many centimetres are in an inch?
One inch is exactly 2.54 centimetres. To convert inches to centimetres, multiply by 2.54. To convert centimetres to inches, divide by 2.54.
How many pounds are in a stone?
One stone is 14 pounds. For example, 11 stone is 154 pounds before adding any remaining pounds.
How many millilitres are in a UK pint?
One UK pint is about 568 millilitres. This is different from a US pint, so choose the correct pint type when converting.
Is mph the same as km/h?
No. Miles per hour and kilometres per hour measure speed using different distance units. To convert mph to km/h, multiply by 1.609344.
Sources and notes
This guide uses stable standard conversion factors and UK-friendly examples. For official UK measurement context, refer to GOV.UK weights and measures guidance. For metric unit definitions, refer to the International System of Units.