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Unit Converter

Convert length, weight, temperature, and data sizes between units, live as you type.

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How to convert units online

  1. Pick a category

    Choose length, weight, temperature, or data size. Sensible default units load for each one.

  2. Enter a value

    Type the number and pick the unit you are converting from. The result recalculates on every keystroke.

  3. Choose the target unit

    Select the unit to convert to and read the converted value in the result field.

  4. Copy the result

    Click Copy result to place the converted number on your clipboard.

Why use this tool

Four everyday categories

Length from millimetres to miles, weight from milligrams to tonnes, temperature in Celsius, Fahrenheit, and Kelvin, and data size from bytes to terabytes.

Exact defined factors

Linear conversions use the international definitions, such as 25.4 mm to the inch and 453.59237 g to the pound, not rounded approximations.

Proper temperature formulas

Celsius, Fahrenheit, and Kelvin are converted with the correct offset formulas through Celsius, not a naive multiplier.

Decimal and binary data units

KB, MB, GB, and TB count in thousands; KiB, MiB, and GiB count in powers of 1024. Both scales share one menu, so you can see why an 8 GB drive reports about 7.45 GiB.

Readable results

Output is rounded to 8 significant digits, switching to exponential notation only for extremely large or small values.

Free and local

No account and no server round trip. The arithmetic happens in your browser as you type.

About this tool

This unit converter covers four categories: length, weight, temperature, and data size. The linear categories convert through a base unit (the metre, the gram, the byte) using exact defined factors, so an inch is precisely 25.4 mm and a pound is precisely 453.59237 g. Temperature is handled separately because its scales are offset rather than scaled, so the converter maps through Celsius with the standard formulas. Results appear as you type and are rounded to eight significant digits.

It handles conversions like cm to inches for a parcel form, kg to pounds for a recipe or a gym plan, Fahrenheit to Celsius for a weather report or an oven, and MB to MiB when a download size and a disk report refuse to agree. That last one is the classic case: storage vendors count a gigabyte as a billion bytes while operating systems count in powers of 1024, and the data category includes both scales so the gap stops being mysterious.

The arithmetic runs in your browser and nothing you type is sent anywhere. For quantities this site treats separately there are dedicated tools: the duration calculator adds and subtracts spans of time across seconds, minutes, hours, days, and weeks, and the aspect ratio calculator solves the proportional math for image and screen dimensions.

Frequently asked questions

Which units can I convert?
Four categories are supported: length (mm, cm, m, km, inch, foot, yard, mile), weight (mg, g, kg, tonne, ounce, pound), temperature (Celsius, Fahrenheit, Kelvin), and data size (bytes, KB, MB, GB, and TB in decimal, plus binary KiB, MiB, and GiB).
How accurate are the conversions?
Conversions use exact internationally defined factors, such as 1 inch equals 25.4 mm and 1 pound equals 453.59237 grams. Results are shown to a sensible number of significant digits for readability.
Is anything sent to a server?
No. Every calculation runs in your browser. Nothing you type is uploaded, sent to a server, or stored.
What is the difference between KB and KiB for data sizes?
KB, MB, and GB are decimal units where each step is 1000 of the previous, used by storage manufacturers. KiB, MiB, and GiB are binary units where each step is 1024, used by most operating systems when reporting memory and file sizes.
How is temperature handled differently?
Temperature is not a simple ratio, so the converter applies the proper formulas, converting through Celsius as a common reference, rather than multiplying by a single factor like the other categories.

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