What this unit converter does
This tool converts values between units across seven everyday categories: length, mass, volume, area, speed, digital storage and temperature. Pick a category, choose the units you are converting from and to, and the result appears instantly as you type. Everything runs locally in your browser — no values are ever uploaded.
Categories you can convert
- Length — millimeters, centimeters, meters, kilometers, inches, feet, yards, miles and nautical miles.
- Mass — milligrams through tonnes, plus ounces, pounds and stone.
- Volume — milliliters, liters, cubic meters and US cooking units like cups, tablespoons and gallons.
- Area — square meters, hectares, square feet, acres and more.
- Speed — m/s, km/h, mph, knots and feet per second.
- Digital storage — both decimal (KB, MB, GB) and binary (KiB, MiB, GiB) sizes.
- Temperature — Celsius, Fahrenheit and Kelvin.
How the conversions work
Most units are converted through a single base unit. For example, every length is expressed in meters internally, so converting 5 kilometers to miles means going from kilometers to meters and then from meters to miles. The factors used are the exact, internationally agreed definitions — one inch is defined as exactly 0.0254 meters, and one pound as exactly 0.45359237 kilograms.
Temperature is different. Because the scales don't share a zero point, a simple multiplication isn't enough. Converting Celsius to Fahrenheit multiplies by 9/5 and then adds 32, while Kelvin shifts the Celsius value by 273.15 degrees. The converter handles this automatically, so −40 °C correctly comes out as −40 °F.
Decimal vs. binary data sizes
Storage is a common source of confusion. Drive manufacturers use decimal units where 1 MB = 1,000,000 bytes, while operating systems often report binary units where 1 MiB = 1,048,576 bytes. That's why a "500 GB" drive can look smaller in your file manager. With this converter you can switch between both systems and see the exact difference.
Popular conversions at a glance
These are some of the most searched conversions. Use the quick-pick buttons above the tool to load any of them instantly.
Length
| Conversion | Result |
|---|---|
| 1 centimeter to inches | 0.3937 in |
| 1 inch to centimeters | 2.54 cm |
| 1 meter to feet | 3.2808 ft |
| 1 kilometer to miles | 0.6214 mi |
| 1 mile to kilometers | 1.6093 km |
Weight
| Conversion | Result |
|---|---|
| 1 kilogram to pounds | 2.2046 lb |
| 1 pound to kilograms | 0.4536 kg |
| 1 ounce to grams | 28.35 g |
| 1 stone to kilograms | 6.3503 kg |
Temperature
| Conversion | Result |
|---|---|
| 0 °C to Fahrenheit | 32 °F |
| 100 °C to Fahrenheit | 212 °F |
| 37 °C to Fahrenheit | 98.6 °F |
| 0 °C to Kelvin | 273.15 K |
Tips for accurate results
- US and UK volumes differ — this converter uses US customary units for cups, pints and gallons.
- Results show up to six significant digits; very large or very small numbers switch to scientific notation so nothing is silently rounded away.
- Use the swap button to reverse the direction without re-selecting units.