Unit Converter
Length, weight, volume, area, speed, time, data and temperature — one value converted to every unit in the category.
Convert units of length, weight, volume, area, speed, time, data and temperature — any unit to any other, with a full conversion table for each category. Instantly, offline, in your browser.
Factors: SI and imperial definitions; temperature uses the standard conversion formulas.
How to use the Unit Converter
- Pick a category (length, weight, temperature and more).
- Choose the from and to units, enter a value.
- Read the result, or browse the full table for that category.
Frequently asked questions
How do I convert km to miles?
Choose Length, set km to mi and enter the value — 1 km = 0.621371 miles.
How do I convert Celsius to Fahrenheit?
Choose Temperature: F = C x 9/5 + 32, so 100 C = 212 F.
Does it cover digital storage?
Yes — bits, bytes, KB, MB, GB and TB in both 1000- and 1024-based units.
How accurate are the conversions?
Factors use standard SI and imperial definitions; results are rounded for display.
Fun facts about Unit Converter
- The metric system was created during the French Revolution (1790s) to replace the chaotic mix of local measurement systems used across France.
- The kilogram was the last SI base unit defined by a physical object — until 2019, when it was redefined using Planck's constant.
- The United States, Liberia and Myanmar are usually cited as the only countries that haven't fully adopted the metric system for everyday use.
- A 'foot' as a unit of measurement literally originated from the length of a human foot — though whose foot varied by region and era.
- Since 1983 the metre has been defined by the speed of light, which is therefore exact by definition: 299,792,458 metres per second.