Unit Converter (Length, Weight, Area, Volume, Temperature, Speed & Data)
ConversionEverything runs locally in your browser — nothing is uploaded
Enter one value and see it in every unit of its category at once, instead of switching dropdowns back and forth. Temperature is an affine scale rather than a ratio — 0 °C is 32 °F, not 0 — so it is handled separately instead of being multiplied by a factor. Data storage keeps the 1000-based KB apart from the 1024-based KiB and labels each row, because mixing those two is exactly where “a 1 TB drive shows up as 931 GB” comes from.
Features
- Seven categories: length, weight, area, volume, temperature, speed and data storage
- Every unit in the category shown at once; click any row to make it the target unit
- Temperature converted as an affine scale, so sign and offset both stay right (-40 °C = -40 °F included)
- Data storage separates 1000-based (KB/MB/GB) from 1024-based (KiB/MiB/GiB) units and labels them
- Includes knots, nautical miles, ounces, stones, US and UK gallons, and other everyday units
- Output is trimmed of floating-point noise (0.1 + 0.2 reads as 0.3, not 0.30000000000000004)
- Temperatures below absolute zero still convert, with a note that they are not physically meaningful
How to use
- Pick a category such as length, weight or temperature
- Enter a number and choose the source and target units
- The table below shows the value in every unit of that category
- Click a row to make it the target, or click Copy to take the result
FAQ
- Why does a 1 TB drive show up as 931 GB?
- Drive makers use powers of 1000 (1 TB = 10^12 bytes) while operating systems report powers of 1024 (1 TiB = 2^40 bytes). The same capacity reads about 7% smaller under the other convention — nothing is missing, two unit systems are being mixed.
- Which one is 1024 — KB or KiB?
- KiB is 1024 bytes; KB strictly means 1000 bytes. In everyday speech “1K” almost always means 1024, but storage and networking specifications use 1000, so both are listed and labelled rather than guessed at.
- Why can’t temperature be converted by multiplying?
- Because the scales do not share a zero: 0 °C is 32 °F. Multiplication only works for units with the same zero point, such as length and weight. Temperature needs the zero shifted first and a factor applied after — an affine transform, which is why it is implemented separately here.
- Are US and UK gallons the same?
- No. A US gallon is about 3.785 litres and a UK gallon about 4.546 litres, a gap of roughly 20%. US and UK fluid ounces, pints and quarts differ too, so both sets are included and the country is named next to each unit.
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