Unit ConverterCenter
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Free Online Unit Converter

Convert length, weight, temperature, volume, data and more - across metric (SI), Imperial, US customary and historical systems. Pick a value, pick two units.

Unit converter

Pick a category, then a value and two units to convert.

Common conversions

centimeters → inchesinches → centimeterskilograms → poundspounds → kilogramsdegrees Celsius → degrees Fahrenheitdegrees Fahrenheit → degrees Celsiusmiles → kilometerskilometers → milesliters → gallonsgallons → litersmeters → feetfeet → metersmiles per hour → kilometers per hourkilometers per hour → miles per hourgigabytes → megabytesmegabytes → gigabytesnewton meters → pound-force feetpound-force feet → newton metersnewton meters → pound-force inchespound-force inches → newton meterspound-force feet → pound-force inchespound-force inches → pound-force feetnewton meters → kilogram-force centimeterskilogram-force centimeters → newton metersliters per 100 km → US miles per gallonUS miles per gallon → liters per 100 kmliters per 100 km → UK miles per gallonUK miles per gallon → liters per 100 kmkilometers per liter → liters per 100 kmliters per 100 km → kilometers per literkilometers per liter → US miles per gallonUS miles per gallon → kilometers per literUS miles per gallon → UK miles per gallonUK miles per gallon → US miles per gallonUS gallons per 100 miles → liters per 100 kmkilometers per liter → miles per liter

All categories

Length11 unitsWeight & Mass10 unitsTemperature4 unitsArea9 unitsVolume14 unitsTime9 unitsSpeed6 unitsData Storage10 unitsPressure7 unitsEnergy8 unitsPower6 unitsAngle6 unitsDensity42 unitsTorque17 unitsFuel Consumption37 units

How to use the unit converter

Pick a category, type a value and choose the unit to convert from and the unit to convert to - the result updates instantly. Every converter also shows a full conversion table, so you can read off common values at a glance. The tool runs entirely in your browser, works offline once loaded and needs no sign-up.

Behind each category is a single base unit - usually an SI base unit such as the meter, kilogram or second. To convert between two units, your value is scaled to that base unit with a fixed conversion factor and then to the target unit, the same dimensional-analysis method you would use by hand. Temperature is the exception: Celsius, Fahrenheit and Kelvin use offset formulas rather than a simple multiplier.

The converter spans the metric (SI), Imperial and US customary measurement systems, so you can move between kilometers and miles or kilograms and pounds in one step. Start with the length converter, weight converter or temperature converter, or pick any category above.

Frequently asked questions

Is the unit converter free?

Yes. Unit Converter Center is completely free, with no sign-up, no limits and no software to install. Every category and conversion is available to use as often as you like.

How accurate are the conversions?

Conversions use the exact internationally defined factors - for example, 1 inch is exactly 2.54 cm and 1 pound is exactly 0.45359237 kg - so results are accurate to many decimal places. Values are only rounded for display.

What is the difference between metric and imperial units?

The metric system (SI) is based on units like the meter, kilogram and liter and scales in powers of ten. The Imperial and US customary systems use units like the inch, foot, mile, pound and gallon. This unit converter lets you move between the two systems instantly.

Does the unit converter work offline?

Yes. Once the page has loaded it runs entirely in your browser with no further network requests, so conversions keep working without an internet connection. Nothing you type ever leaves your device.

How many units can I convert?

The converter covers 14 categories - length, weight, temperature, area, volume, time, speed, data storage, pressure, energy, power, angle, density and torque - with well over a hundred individual units between them.

Do I need to create an account?

No. There is no account, login or download - open the page, choose your units and convert. The tool is built to be fast on both mobile and desktop.