🔁

Unit Converter

New

Convert length, weight and temperature between metric and imperial.

What is the Unit Converter?

A unit converter changes a value from one measurement unit into another within the same category — length, weight or temperature — between metric and imperial systems. For length and weight, it works by converting your value to a common base unit (metres for length, kilograms for weight) using each unit's fixed conversion factor, then converting from that base unit into your target unit. Temperature is different, since Celsius, Fahrenheit and Kelvin don't share a simple multiplication factor — it converts via Celsius as an intermediate step, using C = (F − 32) × 5⁄9 to convert from Fahrenheit, or C = K − 273.15 from Kelvin, then converts from Celsius to the target scale. To convert manually, look up the fixed factor between your two units (for example, 1 inch = 2.54cm) and multiply or divide accordingly.

How it works

Converting between metric and imperial units means multiplying (or dividing) by a fixed conversion factor specific to the two units involved — for example, one inch is defined as exactly 2.54 centimetres, and one kilogram is roughly 2.20462 pounds. Temperature conversion is different from length or weight because the scales don't share a common zero point: converting Celsius to Fahrenheit involves both multiplying and adding (°F = °C × 9/5 + 32), not just multiplying by a single factor.

UK context

The UK is officially metric for most legal, scientific and retail purposes, but imperial units remain in everyday and even legal use in specific areas — road distances and speed limits are measured in miles and mph, draught beer and milk are sold in pints, and people's height and sometimes body weight are still commonly given in feet/inches and stone/pounds respectively. This mix means reliable, quick conversion between the two systems is a genuinely useful everyday skill in the UK, not just a classroom exercise.

Tips

For quick mental estimates, 1 kilometre is roughly 0.62 miles and 1 kilogram is roughly 2.2 pounds — useful rough conversions when you don't need precision.
Always double-check which specific unit you're converting from and to — for example, a UK (imperial) pint and a US pint are different sizes, which can catch people out.
For anything precision-critical (medical dosing, engineering, cooking with strict ratios), use exact conversion factors rather than rounded estimates.

Frequently asked questions

Why does the UK use both metric and imperial units?

The UK officially adopted the metric system for most legal, scientific and retail contexts, but imperial units remain in everyday and some legal use for specific things — road distances and speed limits, pints of beer and milk, and people's height are well-known examples that stayed imperial by convention or specific regulation.

How do you convert Celsius to Fahrenheit?

Multiply the Celsius temperature by 9/5, then add 32. Unlike length or weight conversions, temperature scales don't share a common zero point, so the formula needs both a multiplication and an addition step, not just a single conversion factor.

Is a UK pint the same as a US pint?

No — an imperial (UK) pint is larger than a US liquid pint. This applies to gallons as well, so US and UK/imperial volume conversions aren't directly interchangeable without accounting for the difference.