Unit Converter Online
Convert length, weight, temperature, volume, area, speed, and data size online—locally, with explicit units.
Introduction
Convert measurements online without a round trip to a server: length, weight, temperature, volume, area, and speed for physical quantities, plus data size and number bases for digital ones. Every unit is named explicitly—US and imperial gallons are separate options, and decimal megabytes are distinct from binary mebibytes—so a conversion never hinges on an assumption.
Featured tools
Length Unit Converter
Convert length units instantly in your browser.
- length
- unit-converter
- converter
- measurement
Weight Unit Converter
Convert weight and mass units locally.
- weight
- unit-converter
- converter
- measurement
Temperature Converter
Convert Celsius, Fahrenheit, and Kelvin instantly.
- temperature
- unit-converter
- converter
- measurement
Volume Unit Converter
Convert volume units for cooking, science, and more.
- volume
- unit-converter
- converter
- measurement
Area Unit Converter
Convert area units like acres, hectares, and m².
- area
- unit-converter
- converter
- measurement
Speed Unit Converter
Convert speed units like mph, km/h, and knots.
- speed
- unit-converter
- converter
- measurement
Data Size Converter
Convert bytes, KB, MB, GB, TB, and binary units.
- data-size
- unit-converter
- converter
- storage
Number Base Converter
Convert bin/oct/dec/hex locally with BigInt.
- binary
- hex
- octal
- decimal
Roman Numeral Converter
Convert numbers to and from Roman numerals.
- roman-numerals
- numbers
- converter
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Frequently asked questions
- Does this unit converter work offline?
- After the page loads, conversions are computed in the browser, so a dropped connection does not interrupt them. Nothing you type is sent to a server.
- How do I convert Celsius to Fahrenheit correctly?
- Multiply by 9/5 and add 32; reverse the order to go back. Temperature Converter applies the full formula, including the offset that quick mental estimates skip.
- Why does my storage conversion look off by 7%?
- You are probably mixing decimal and binary prefixes. A gigabyte is 1,000,000,000 bytes while a gibibyte is 1,073,741,824—Data Size Converter exposes both explicitly.
- How much should I round a converted value?
- Match the precision of the source measurement. Reporting many decimals from a rounded input implies accuracy the original figure never had.
- Can I convert between number bases here?
- Yes. Number Base Converter handles binary, octal, decimal, and hexadecimal with arbitrary-precision arithmetic so long values keep every digit.