Unit converter
Convert between length, weight, volume, speed, area, data, temperature, time, and energy units instantly.
- 100% free
- No sign-up
- No limits
- Instant results
1 Millimeter (mm) = 0.1 Centimeter (cm)
1 Millimeter = 0.1 Centimeter
- 9 unit categories with 70+ units
- Temperature: Celsius, Fahrenheit, Kelvin
- Time: milliseconds to years
- Energy: joules, calories, BTU, kWh
- Real-time conversion as you type
- Shows conversion formula
- 100% browser — no server calls
What is Unit Converter?
A unit converter is a tool that translates measurements from one unit system to another — for example, converting kilometers to miles, Celsius to Fahrenheit, or kilojoules to calories.
This free online unit converter covers nine major categories: length, weight, volume, speed, area, data storage, temperature, time, and energy, with over 70 individual units. Temperature conversions use proper formulas (not simple multiplication), and all conversions happen in real time as you type. The tool shows the exact conversion formula so you understand the math behind every result. Whether you are a developer calculating file sizes, a student solving physics problems, an engineer converting metric to imperial, or a cook scaling recipes, this converter handles it all in one place.
How to use Unit Converter
- 1
Select a category
Choose from Length, Weight, Volume, Speed, Area, Data, Temperature, Time, or Energy using the category tabs. Each category loads its own set of units relevant to that measurement type.
- 2
Pick your units and enter a value
Select the source unit in the From dropdown and the target unit in the To dropdown. Type a number in the value field. Use the swap button to quickly reverse the conversion direction.
- 3
Read and copy the result
The converted value appears instantly below the input along with the conversion formula. Click the Copy button to copy the full conversion result to your clipboard.
Everything this tool
does for you
- Nine conversion categories: length, weight, volume, speed, area, data, temperature, time, energy
- Over 70 units with precise conversion factors
- Temperature: Celsius, Fahrenheit, Kelvin with correct formulas
- Time: milliseconds to years including months and weeks
- Energy: joules, calories, BTU, watt-hours, electron-volts
- Real-time conversion that updates instantly as you type
- One-click swap button to reverse from and to units
- Displays the conversion formula for every conversion
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