Most everyday mistakes with units come from mixing up systems — reading a recipe in cups when your kitchen scale only shows grams, or estimating a US gallon as if it were the larger UK imperial gallon. This converter covers the ten categories people run into most often: length, mass, volume (including the oil barrel, a unit still used throughout the energy industry), temperature, area, speed, time, digital data, pressure, and energy.
Each category uses precise, standard conversion factors rather than rounded approximations — for example, one US gallon converts at exactly 3.785411784 litres, and one nautical mile at exactly 1852 metres, matching the official international definitions rather than a rough estimate.
If you find yourself converting the same pair of units repeatedly — say, feet to metres for a home renovation, or Fahrenheit to Celsius when checking the weather abroad — star it with Add to favorites. Up to three conversions are saved directly in your browser's local storage, no account required, and the most recently used one loads automatically the next time you open the page.
An oil barrel (bbl) equals exactly 158.987294928 litres. It's the standard unit for quoting crude oil volumes worldwide, even in countries that otherwise use the metric system, which is why it's included alongside the more common volume units.
Yes. Every conversion factor used here is the internationally defined exact value (for example, 1 inch = 0.0254 m, 1 pound = 0.45359237 kg), not a rounded approximation, so results stay accurate even for very large or very small numbers.
No. All calculations happen directly in your browser. The only thing saved is your list of favorite conversions, stored locally on your device — nothing is transmitted to a server.