Free unit converter for everything you measure
Convert length, weight, temperature, volume, area, speed and more — with accurate formulas, conversion tables and real-world examples.
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11 categories · 114 units · thousands of conversions
Length
15 unitsConvert meters, kilometers, miles, feet, inches and more.
Weight
12 unitsConvert kilograms, grams, pounds, ounces, stones and more.
Volume
15 unitsConvert litres, millilitres, gallons, cups, fluid ounces and more.
Temperature
4 unitsConvert Celsius, Fahrenheit, Kelvin and Rankine.
Area
12 unitsConvert square metres, hectares, acres, square feet and more.
Time
10 unitsConvert seconds, minutes, hours, days, weeks, months and years.
Speed
10 unitsConvert km/h, m/s, mph, knots, Mach and more.
Energy
10 unitsConvert joules, calories, kilowatt-hours, BTU and more.
Pressure
10 unitsConvert bar, psi, Pa, atm, mmHg and more.
Power
8 unitsConvert watts, kilowatts, horsepower, BTU/h and more.
Data
8 unitsConvert bits, bytes, kilobytes, megabytes, gigabytes and more.
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Why UnitConv?
Built for accuracy, speed and everyday use.
Instant results
Type a value and see the converted number as you type — no button, no wait.
NIST-accurate
Conversion factors sourced from NIST and BIPM standards for reliable results.
Mobile-first
Designed for phones first — thumbs, fast typing and one-handed use.
Formulas included
Every page shows the formula, a table of common values and real-world examples.
European examples
We distinguish US and UK gallons, °C-first temperatures and metric by default.
100% free
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