Unit Converter
Convert a value between units of length, mass, temperature, volume, area, speed, data size, or time. Runs entirely in your browser.
About this tool
A fast, private unit converter that runs entirely in your browser — nothing is uploaded to a server. Enter a value, the unit you have, and the unit you want, and get the converted result instantly.
Supported categories and units
- Length — metre, kilometre, centimetre, millimetre, micrometre, nanometre, mile, yard, foot, inch, nautical mile.
- Mass — kilogram, gram, milligram, microgram, tonne, pound, ounce, stone, US ton, UK (long) ton.
- Temperature — Celsius, Fahrenheit, Kelvin, Rankine, Réaumur.
- Volume — litre, millilitre, cubic metre, cubic centimetre, US/UK gallon, quart, pint, cup, fluid ounce, tablespoon, teaspoon.
- Area — square metre, square kilometre, square centimetre, square millimetre, hectare, acre, square mile, square yard, square foot, square inch.
- Speed — metre per second, kilometre per hour, mile per hour, foot per second, knot.
- Data size — bit, byte, and decimal (KB, MB, GB, TB, PB) plus binary (KiB, MiB, GiB, TiB) multiples.
- Time — nanosecond, microsecond, millisecond, second, minute, hour, day, week, month, year.
How to use
- Type the number you want to convert.
- Enter the unit you are starting from (e.g.
km,lb,celsius,gallon). - Enter the unit you want to convert to (in the same category).
Unit names, plurals, and common symbols/aliases all work — for example m,
metre, and meters are interchangeable, as are c/celsius and mph/mile per hour. The "from" and "to" units must belong to the same category; you can
convert metres to feet, but not metres to kilograms.
Notes on accuracy
Conversions use exact internationally-defined factors where they exist (for example 1 inch = 2.54 cm exactly, 1 pound = 0.453 592 37 kg exactly). Months use the average Gregorian month length and years use the Julian year (365.25 days). Data sizes distinguish decimal SI multiples (KB = 1000 bytes) from binary IEC multiples (KiB = 1024 bytes).
FAQ
Do I have to select a category before converting?
No — the category is inferred from the units you type. If the two units don't
belong together you get a specific error rather than a wrong answer, e.g.
converting metre to kilogram reports "cannot convert metre (length) to
kilogram (mass)".
Is a gigabyte (GB) the same as a gibibyte (GiB)?
No, and the tool keeps them separate: kb/mb/gb/tb/pb are decimal SI
multiples (1 GB = 1000 MB = 10⁹ bytes) while kib/mib/gib/tib are binary
IEC multiples (1 GiB = 1024 MiB = 2³⁰ bytes). You can convert between the two
systems directly — 1 GiB ≈ 1.074 GB. Bits are supported too (8 bits = 1 byte).
Are "gallon", "pint" and "cup" US or imperial measures?
The bare names default to US measures: gallon, quart, pint, cup and
fluid-ounce are all US units. For the imperial versions use uk-gallon or
imperial-gallon. Likewise ton is ambiguous, so use us-ton/short-ton or
long-ton/imperial-ton explicitly.
How many digits of precision does the result keep?
Results are rounded to 12 significant figures with trailing zeros trimmed, and extreme magnitudes (10¹⁵ and up, or below 10⁻⁹) switch to scientific notation. The underlying factors are the exact defined values where one exists, so round-trips like metres → feet → metres come back to the number you started with.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool unit-converter "5" 'from=km' 'to=miles'New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/unit-converter/?value=5&from=km&to=milesMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.