Unit Converter guide
Unit Converter: Metric and Imperial Conversions
Use our unit converter to convert length, weight, volume, area, speed, temperature, energy, pressure, time and data between metric and imperial units.
By the AllCalculator editorial teamUpdated 15 October 20262 min read
The UK uses a mix of metric and imperial units: miles on road signs, pints in pubs, stones on the bathroom scales and metres everywhere else. Our Unit Converter handles them all.
How to use the calculator (Unit Converter)
- Choose what to convert: length, weight, volume, area, speed, time, energy, pressure, data or temperature.
- Enter the value.
- Choose the units to convert from and to.
A table also shows the value in every unit in that category.
Common UK conversions
| From | To | Multiply by |
|---|---|---|
| Miles | Kilometres | 1.609 |
| Feet | Metres | 0.3048 |
| Inches | Centimetres | 2.54 |
| Stone | Kilograms | 6.350 |
| Pounds | Kilograms | 0.4536 |
| UK pints | Litres | 0.5683 |
| UK gallons | Litres | 4.546 |
| Acres | Hectares | 0.4047 |
UK and US measures aren't the same
A UK pint is 568mL, but a US pint is 473mL. A UK gallon is about 4.55 litres; a US gallon is about 3.79 litres. That's why fuel economy in UK mpg is higher than the same car in US mpg.
Temperature
Temperature uses a formula rather than a multiplier:
- °F = °C × 9/5 + 32
- °C = (°F − 32) × 5/9
- K = °C + 273.15
So 100°C is 212°F, and 0°C is 32°F.
A worked example
With the calculator's default settings, 26.2 miles (a marathon) is 42.16 kilometres.
For lengths in feet and inches with fractions, use our Construction Calculator. For currency, see our Currency Calculator Euro and USD to British Pound Calculator.
Frequently asked questions
How many kilograms in a stone?
6.35kg. There are 14 pounds in a stone.
What's the difference between a kilobyte and a kibibyte?
A kilobyte is 1,000 bytes and a kibibyte is 1,024 bytes. Storage makers use kilobytes; some operating systems use kibibytes.
Are the conversions exact?
They use the exact legal definitions, such as 1 inch = 25.4mm, rounded for display.
Bookmark the Unit Converter for recipes, DIY, travel and homework.
Sources and further reading
Links open official and independent websites in a new tab.
This guide is general information to help you understand your options. It isn't financial, tax, legal or building advice and doesn't take your personal circumstances into account. Figures were checked when the guide was last updated and can change, so confirm anything important with GOV.UK, HMRC, a regulated adviser or a qualified tradesperson.