British Weights & Measures Converters
Instant conversion calculators for every British imperial and metric measurement. From kg to stone to miles to km — all the conversions Britain actually uses, every day.
Why Britain Has Two Measurement Systems
Britain officially adopted the metric system in 1965, yet decades later the country still uses stone for body weight, miles for road distances, pints in pubs and Fahrenheit in casual conversation. This uniquely British mixing of imperial and metric makes conversion calculators more essential here than almost anywhere else in the world.
Common UK Weights & Measures Questions
How many kg is a stone?+
One stone is exactly 6.35029318 kilograms. Conversely, 1 kg equals approximately 0.157 stone, or 2.205 pounds. Stone is the most common unit for body weight in the UK and Ireland, even though it is not used elsewhere in the world.
How many centimetres are in an inch?+
There are exactly 2.54 centimetres in one inch. This is a fixed, internationally defined value. So 1 foot (12 inches) equals 30.48 cm, and 1 metre equals approximately 39.37 inches. This conversion is essential for heights, where the UK commonly describes people in feet and inches.
How many miles in a kilometre?+
One kilometre equals 0.621371 miles. Equivalently, one mile is 1.60934 km. The UK is one of only three countries in the world still using miles for road distances. Speed limits, road signs and distances on motorways and A-roads are all expressed in miles and mph.
What is 37°C in Fahrenheit?+
37°C is 98.6°F — normal human body temperature. The formula to convert Celsius to Fahrenheit is: (°C × 9/5) + 32 = °F. So 37 × 1.8 = 66.6, plus 32 = 98.6°F. For everyday use: 0°C = 32°F (freezing), 100°C = 212°F (boiling).
How many litres in a UK gallon?+
One UK (imperial) gallon equals 4.54609 litres. Note that a US gallon is different — it equals only 3.785 litres, about 17% less than a UK gallon. This distinction matters for fuel consumption: UK mpg figures are calculated using the larger imperial gallon, so they appear better than US mpg for the same vehicle.
Why does the UK still use imperial measurements?+
Britain officially adopted the metric system in 1965 and completed most transitions by the 1970s–80s. However, several imperial units have legal or cultural protection: road distances and speeds must be shown in miles by law, pints must be used for draught beer and milk in returnable containers, and body weight in stone/pounds is deeply embedded in everyday British culture despite no legal requirement.