Unit Converter
Length, weight, temperature, volume, area, speed and data storage — converted instantly as you type.
About this tool
Recipes in cups, packages in pounds, weather in Fahrenheit, files in gigabytes — the world refuses to pick one system. This free unit converter handles length, weight, temperature, volume, area, speed and digital storage with exact, internationally defined conversion factors, updating the result the instant you type.
No ads between you and the answer, no server round-trip, no app to install. Pick a category, choose your units, type a number.
How to convert units
- Pick a category (length, weight, temperature…).
- Enter a value and choose the from and to units.
- The result appears instantly — use ⇄ to flip the direction.
Frequently asked questions
Which unit categories are supported?
Seven categories: length, weight and mass, temperature, volume, area, speed, and digital storage — covering metric, imperial and US customary units, from millimeters and inches up to terabytes and knots.
How accurate are the conversions?
Conversions use the exact internationally defined factors — for example one inch is exactly 25.4 millimeters and one pound is exactly 0.45359237 kilograms — so results are as accurate as your input.
Why is temperature different from the other categories?
Celsius, Fahrenheit and Kelvin scales have different zero points, not just different step sizes, so converting requires an offset formula rather than a simple multiplication. The tool handles this automatically.
Are these US or UK measurements?
Gallons, fluid ounces and cups follow the US definitions, which are the ones most commonly meant online. Metric units are identical everywhere.
Does the converter work offline?
Once the page has loaded, yes — all conversion math runs locally in your browser with no server calls, so a dropped connection doesn't interrupt you.