Unit Conversion Calculator
Convert between any two units of length, weight, temperature, area, volume, speed, time and data.
All calculations happen locally in your browser — nothing is uploaded, stored or tracked.
Pick a category
Choose length, weight, temperature or any of the eight categories.
Choose the units
Select the unit you have and the unit you want.
Enter the value
The conversion updates as you type.
What Is a Unit Conversion Calculator?
A unit conversion calculator changes a measurement from one unit to another — inches to centimetres, kilograms to pounds, Celsius to Fahrenheit. It uses fixed conversion factors, so results are exact for the given inputs.
Eight categories are covered: length, weight, temperature, area, volume, speed, time and data storage. Temperature is handled separately from the other categories because it uses an offset formula (Celsius to Fahrenheit is not a simple multiplication), while everything else converts by a fixed factor.
The Conversion Formula
Every unit in a category has a factor expressed relative to a base unit (for example, metres for length). Converting between two units divides their factors. Temperature uses the standard formulas for Celsius, Fahrenheit and Kelvin.
Your data never leaves your device.
Every calculation on this site runs in your browser using vanilla JavaScript. Nothing is uploaded, stored or tracked.
- 100% local, client-side calculations
- No data stored on any server
- No tracking, no analytics, no ads scripts
- Works offline once loaded
Frequently Asked Questions
How many kilograms are in a pound?
One pound is exactly 0.45359237 kilograms. The calculator uses this precise factor.
How do I convert Fahrenheit to Celsius?
Subtract 32, then multiply by 5/9: (°F − 32) × 5/9. The temperature category applies this formula automatically.
Is the mile-to-kilometre conversion exact?
One international mile is exactly 1.609344 kilometres.
Does this work offline?
Yes — all conversion factors are built into the page, so it works with no internet connection.
What is the base unit for each category?
Metres (length), kilograms (weight), square metres (area), cubic metres (volume), metres per second (speed), seconds (time) and bytes (data).