Easy Converter

Unit Converter

Convert length, weight, temperature, volume, area, speed and time between metric and imperial units. Live-updating, accepts decimals, supports negative temperatures and works equally well for cooking recipes, school homework, fitness tracking and engineering calculations.

How to use

  1. 1

    Pick a category

    Length, weight, temperature, volume, area, speed or time.

  2. 2

    Enter a value and unit

    Type the value and pick the input unit.

  3. 3

    Read every other unit

    All compatible units update simultaneously. Copy any of them with one click.

Technical details

Unit conversion is multiplication by a conversion factor, except for temperature, where the offset between scales requires an affine transformation. The converter ships with a precise table of SI conversion factors and applies them with full IEEE 754 double precision, which gives ~15 significant digits — more than enough for any practical use.

Length: 1 inch = 25.4 mm exactly (since 1959 international yard agreement). All other length conversions chain from this. Common pitfalls include the survey foot (used by US land surveys, slightly different) and the nautical mile (1852 m, not 1609).

Weight: the converter distinguishes mass (kg, lb, oz) from force (newton, pound-force). On Earth, multiplying mass in kg by 9.80665 gives the weight in newtons. For everyday use the two are conflated.

Temperature: Celsius and Fahrenheit are linear but not proportional. `F = C × 9/5 + 32` and `C = (F − 32) × 5/9`. Kelvin is just `C + 273.15`. The converter handles negative values correctly and warns when you go below absolute zero.

Frequently asked questions

How precise is the conversion?
15 significant digits internally, with conversion factors taken from NIST and the BIPM.
Does it handle negative temperatures?
Yes. The converter warns only when you go below absolute zero (−273.15 °C).
Are US and UK gallons different?
Yes. 1 US gallon = 3.785 L; 1 UK (imperial) gallon = 4.546 L. The converter offers both.
What about the survey foot?
It differs from the international foot by 2 parts per million. Only relevant for US land surveying. The converter uses the international foot by default.
Is anything sent to a server?
No. All conversion factors are bundled and the math is local.
Reviewed by:Easy Converter Engineering Team

This tool was tested and calibrated by our engineering team. All processing happens locally in your browser — your files and data never leave your device.