The best free unit converter gives instant results as you type, uses the exact standard conversion factors, and works without signup, ads or sending your input to a server. A browser-based converter covers length, weight, temperature and volume, and keeps working offline once the page has loaded.
Free length and distance converter. Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles instantly as you type.
Open Length Converter → Free toolFree weight and mass converter. Convert between grams, kilograms, metric tonnes, ounces, pounds, and stones instantly with exact factors as you type.
Open Weight / Mass Converter → Free toolFree temperature converter. Convert between Celsius, Fahrenheit, and Kelvin instantly with correct offset formulas, updating live as you type a value.
Open Temperature Converter →Three things: correct factors, speed and privacy. The factors should be the exact defined values, such as one inch being exactly 2.54 cm and one pound exactly 0.45359237 kg, not loose approximations. The result should update as you type, with no page reload. And the math should run in your browser, so nothing you enter is transmitted anywhere.
A general converter that handles length, weight, temperature, volume and more is the bookmark for everyday use. Dedicated single-pair pages, like kg to lbs or Fahrenheit to Celsius, are quicker when you always convert the same units, because the right pair is preselected. Both styles are free and run entirely client-side.
Yes. There is no account, no ads and no usage cap. The conversion runs in your browser.
Once the page has loaded, the math runs locally, so it keeps working without a connection.
Length, weight, temperature and volume, plus dedicated converters for area, speed, pressure, energy, data storage and cooking measures.