WhatIs.site Unit Converter
Free unit converter for length, mass, volume, temperature, area, time, speed, energy, pressure, and data storage. Metric and imperial. Instant calculation in your browser.
About this converter
This is a no-frills converter for the 10 unit categories people actually look up. Pick a category. Type a value. Get an answer. The conversion factors come from SI definitions and NIST tables and are accurate to at least 6 significant figures for everyday use.
Temperature is special: it uses an offset scale, not a ratio scale, so the math is slightly different. The converter handles all six pairings of Celsius, Fahrenheit, and Kelvin correctly.
Want the concept first?
For background, see explainers in our Science, Engineering, and Mathematics categories.
Frequently asked questions
Which units does this converter support?
Length, mass/weight, volume, temperature, area, time, speed, energy, pressure, and data storage. Pick a category at the top, then choose your "from" and "to" units. Everything is computed instantly in your browser.
How accurate is it?
Conversion factors come from SI definitions and NIST tables. For everyday use the precision is more than sufficient. Results display up to 6 significant figures and use scientific notation for very large or very small numbers.
How does temperature conversion work?
Temperature is an offset scale, not a ratio scale, so the math differs from other categories. Celsius to Fahrenheit is F = C × 9/5 + 32. Celsius to Kelvin is K = C + 273.15. The converter handles all six pairings.
Is metric or imperial supported?
Both, and the conversions between them are exact where the SI definition is exact (e.g., 1 inch = 0.0254 m exactly). Imperial fluid units default to US measurements; UK/imperial gallon is also offered where it matters.
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