Convert between length, weight, temperature, area, and speed units. Type into any field — every other field updates instantly.
A fast, no-fuss converter for the units you actually use day to day. It handles five categories — length, weight (mass), temperature, area, and speed — bridging metric and imperial with standard SI factors so the numbers match what you'd find in a textbook or engineering table.
Type into any field and every other field in the category updates instantly, so you can read off all units at once instead of converting one pair at a time. People use it to:
Everything runs local and in-browser. The conversion factors are bundled with the page, so no values you type are ever sent to a server, and the tool keeps working offline once loaded.
Five categories: length, weight (mass), temperature, area, and speed. Each one includes both metric and imperial units, such as meters and feet, kilograms and pounds, or km/h and mph.
Yes. Every category mixes metric and imperial units in the same view, so you can go from millimeters to inches, kilometers to miles, kilograms to pounds, square meters to acres, or m/s to mph directly.
Celsius to Fahrenheit is (C × 9/5) + 32, Fahrenheit to Celsius is (F − 32) × 5/9, and Kelvin is C + 273.15. All conversions route through Celsius as the common base.
Conversions use standard SI factors and results are shown to 10 significant figures. Very large or very small numbers switch to scientific notation so precision is never lost to rounding.
Everyday ones like 1 foot = 12 inches, 1 mile = 1.609 km, 1 pound = 0.454 kg, 1 stone = 14 lb, 1 acre = 4047 m², 1 hectare = 10000 m², and 1 knot = 1.852 km/h. The Quick Reference card lists more per category.
Yes. The conversion factors are bundled with the page and all math runs locally, so nothing you type is ever sent to a server.
Yes. Once the page has loaded, the converter needs no internet connection and keeps working offline.