Unit Converter
Convert between units of length, weight and temperature. Everything updates live and stays on your device.
Free online unit converter
This unit converter makes it easy to switch between the measurement systems you use every day. Pick a category — length, weight or temperature — choose the units you want to convert from and to, and the result appears instantly. It's perfect for cooking, travel, DIY projects, science homework and quickly checking metric against imperial figures.
Accurate and completely private
Length and weight conversions use precise ratios to a base unit, while temperature is handled with the exact Celsius, Fahrenheit and Kelvin formulas rather than simple multiplication. Every calculation runs directly in your browser, so nothing you enter is ever sent to a server or stored anywhere.
Frequently asked questions
Why isn't temperature just a ratio like the others?
Temperature scales have different zero points, so converting requires addition and subtraction as well as scaling. We use the standard formulas — for example °F = °C × 9/5 + 32 — to keep results accurate.
How many units are supported?
Length covers millimetres through miles, weight covers milligrams through tonnes, and temperature covers Celsius, Fahrenheit and Kelvin. Just switch the category to see the available options.