Fast · accurate · private
Free online unit converter.
Convert common measurement units instantly with precise math, clear formulas, and zero fuss. Your values never leave your browser.
Use ↑ and ↓ to choose, then Enter to open.
Popular now
Millimeters to inches
One of the web’s most searched conversions, ready instantly.
All converters
Choose a measurement
Ten focused categories. No currencies, accounts, or hidden calculations.
Length
Convert metric, imperial, and nautical distances.
9 units →Mass
Convert everyday metric and imperial mass units.
7 units →Temperature
Convert Celsius, Fahrenheit, and Kelvin accurately.
3 units →Area
Convert square metric and customary measurements.
9 units →Volume
Convert metric, US customary, and imperial volumes without mixing standards.
10 units →Speed
Convert road, athletic, marine, and scientific speeds.
4 units →Pressure
Convert common engineering and atmospheric pressure units.
6 units →Energy
Convert mechanical, electrical, food, and thermal energy.
8 units →Power
Convert electrical and mechanical power ratings.
4 units →Data Storage
Convert decimal storage and binary IEC units precisely.
9 units →Learn the why
Conversion guides
Plain-language references that explain the systems behind the numbers.
Metric vs imperial
Understand where the systems differ and which units belong to each.
Read guide →FormulaTemperature conversion
See why Celsius and Fahrenheit need both a multiplier and an offset.
Read guide →Digital storageGB vs GiB
Learn the practical difference between decimal and binary capacity.
Read guide →Built for confidence
Clear math. Useful context.
Locally calculated
Nothing you type is transmitted for calculation.
Standards-aware
US and imperial volume units remain distinct.
Precision by default
Results retain meaningful digits and handle extremes.