About UnifyUnits

Who builds it

UnifyUnits is built and maintained bySatheez, a software engineer. The site puts the calculator first, with unit definitions, formulas, and examples below it. You can get a result quickly or read through the calculation.

You can report an error or suggest a conversion through thecontact page. If a result looks wrong, include the value and units you used.

Where the numbers come from

The conversion pages cite measurement references, including:

• NIST Special Publication 811 explains SI usage and lists conversion factors between SI and non-SI units.
• BIPM SI Brochure (9th edition) defines the SI base units. It is maintained by the International Bureau of Weights and Measures.

Exact legal definitions are used where they exist. For example, the international foot is exactly 0.3048 meters under the 1959 international yard and pound agreement, and the pound is exactly 0.45359237 kilograms. Unit definitions shown on converter pages cite these same standards.

How the conversion engine works

The calculator uses Decimal.js for decimal arithmetic. This helps avoid common rounding artifacts during calculations, such as the0.1 + 0.2 ≠ 0.3 problem in binary floating-point math. Results are rounded for display.

Most conversions use a shared base unit, such as meters for length or kilograms for mass. The calculator converts your value to that base unit, then to the unit you chose. Other conversions need a formula: Celsius to Fahrenheit, for example, includes both multiplication and an offset.

Accuracy and corrections

Displayed results and factors are rounded for readability. Keep your original measurement when doing another conversion, and round the final answer to match its accuracy. Each converter page shows the calculation steps and source reference so you can check the method.

If you find a factor, definition, or fact that disagrees with the cited standards, report it through thecontact page. Include a link to the page and the reference you checked.