Unit Converter
Instantly convert any unit — length, weight, temperature, speed and more
Pick a category, type a figure into either box, and every equivalent updates as you go — there's nothing to submit and no Calculate button to press. It handles the conversions most of us actually reach for, from centimetres to inches and kilograms to stones, through to the ones that only crop up now and then: knots, hectares, gigabits. If it's your own height you're converting, there's a dedicated feet-and-inches tool a little further down the page.
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Length Converter
All Length Conversions
A few conversions worth knowing by heart
Some of these come up often enough to memorize, and holding a rough figure in your head is the easiest way to catch a converter — any converter — that has quietly been given the wrong unit.
- An inch is exactly 2.54 cm. That is not a rounded value but the definition agreed internationally in 1959.
- A mile is a little over 1.6 km, so turning miles into kilometres means adding roughly three-fifths.
- A kilogram is about 2.2 lb, and a stone is 14 lb, or 6.35 kg.
- Water freezes at 0 °C (32 °F) and boils at 100 °C (212 °F) at sea level.
The pint-and-gallon trap. British and American units share their names but not their sizes, which catches people out constantly. An imperial pint is 568 ml; an American pint is only 473 ml. An imperial gallon holds 4.55 litres against the US gallon's 3.79. A recipe or a fuel-economy figure quoted simply in "gallons" can therefore be a fifth adrift, depending on the country it came from — which is exactly why the Volume category keeps UK and US measures on separate lines rather than lumping them together.
❓ Frequently Asked Questions
How do I convert kilometres to miles? ▼
Select the "Length" category, enter your value in kilometres, and the miles equivalent appears instantly alongside all other length units. 1 km = 0.621371 miles. For a quick mental estimate, multiply km by 0.6.
How do I convert Celsius to Fahrenheit? ▼
Select the "Temperature" category and enter degrees Celsius. The Fahrenheit conversion appears automatically using the formula °F = (°C × 9/5) + 32. For example, 20°C = 68°F, 100°C = 212°F (boiling point of water).
How do I convert kilograms to pounds? ▼
Select "Weight / Mass" and enter kilograms. 1 kg = 2.20462 lbs. So 70 kg = 154.3 lbs. The converter also shows stones and ounces simultaneously.
What is the difference between mass and weight? ▼
Mass is the amount of matter in an object (measured in kg or lbs) and stays the same everywhere. Weight is the force of gravity acting on that mass (measured in Newtons) and varies slightly by location. In everyday use, "weight" and "mass" are used interchangeably and both use kg/lbs.
Can I convert cooking measurements? ▼
Yes — use the "Volume" category for fluid conversions (litres, millilitres, cups, fluid ounces, tablespoons, teaspoons). Note that US cups and metric measurements differ — 1 US cup = 236.6 ml. For converting weight-based cooking measurements, use the "Weight" category.
📏 Height Converter
Convert height between centimetres and feet & inches
| cm | Feet & inches | cm | Feet & inches |
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