Unit Converter
Convert between units of length, weight, temperature, and more.
About Unit Converter
Whether you are translating a recipe from cups to millilitres, checking how many kilometres are in a mile, or working out Fahrenheit in Celsius, this free unit converter gives you the answer instantly. It covers seven categories — length, weight, temperature, volume, area, speed, and data storage — with the metric and imperial units people actually use. There is no sign-up and nothing to install, and every conversion is calculated locally in your browser, so the values you enter never leave your device.
The converter is built for speed and clarity. Results update live as you type, a swap button reverses the direction in one click, and the exact conversion formula is displayed under every result so you can see how the number was derived — useful for homework, engineering checks, or just satisfying curiosity. A quick-reference grid also shows what one of your selected unit equals in every other unit of the category, turning a single lookup into a full metric to imperial conversion table at a glance.
How to convert units online
- 1Pick a category tab at the top — Length, Weight, Temperature, Volume, Area, Speed, or Data.
- 2Enter the number you want to convert in the Value field.
- 3Choose your starting unit in the From dropdown and your target unit in the To dropdown — the result updates instantly as you type.
- 4Click the swap button between the dropdowns to reverse the conversion direction.
- 5Check the formula shown under the result, and use the quick-reference grid below to see your value’s equivalent in every other unit of the category.
Frequently asked questions
Which units can I convert?
Length (millimetres through miles), weight (milligrams through metric and imperial tons), temperature (Celsius, Fahrenheit, Kelvin), volume (millilitres, litres, US gallons, cups, tablespoons and more), area (square millimetres through acres and hectares), speed (m/s, km/h, mph, knots), and data (bits through petabytes).
How does temperature conversion work?
Temperature uses the proper offset formulas rather than a simple multiplier: Fahrenheit = Celsius × 9/5 + 32, and Kelvin = Celsius + 273.15. The tool converts between any pair of Celsius, Fahrenheit, and Kelvin and displays the exact formula it applied under the result.
Do data conversions use 1000 or 1024?
The data category uses the binary convention: 1 kilobyte = 1024 bytes, 1 megabyte = 1024 kilobytes, and so on up to petabytes. This matches how operating systems typically report file sizes, though drive manufacturers often advertise using decimal (1000-based) units.
How accurate are the results?
Conversions use precise standard factors — for example 1 inch = 0.0254 m and 1 pound = 0.45359237 kg exactly — and results are shown to up to 12 significant digits, switching to scientific notation for extremely large or small values.
Is my data sent anywhere?
No. Every conversion is computed locally in your browser with JavaScript — nothing you enter is uploaded, logged, or stored on any server.
Is this unit converter free?
Yes — completely free, with no sign-up, no ads gating the result, and no limit on how many conversions you can run.
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