Type the number, then start typing the unit you have (like "miles"), press Tab, type the unit you want (like "kilometers"), and press Enter or click Calculate. The ⇄ button swaps the two units instantly. You can also tap any category chip to pre-fill an example.
Yes — we use the internationally defined conversion factors (for example, 1 inch = exactly 2.54 cm, 1 mile = exactly 1609.344 m). Results are rounded to 6 decimal places for readability. For medical, engineering, or aviation decisions, always double-check critical numbers against an authoritative source.
Eleven categories: length, weight, volume, temperature, area, speed, data, time, pressure, energy, and power — over 60 units in total, including everyday ones like cups, teaspoons, psi, food calories (kcal), and horsepower. Currency conversion is coming later. Missing one you need? Tell us.
Really free, no login, no pop-ups. In the future the site may show a small number of non-intrusive ads at the edges of the page — never inside the converter or blocking your reading.
Nothing leaves your device. All conversions are computed locally in your browser — we never see what you convert. See our Privacy Policy for the full details.
Most units scale by multiplication (1 kg = 2.2 lb, 2 kg = 4.4 lb). Temperature scales have different zero points, so they need a formula instead: °F = °C × 9/5 + 32. That's why 0 °C = 32 °F, not 0 °F.
The site is fully mobile-friendly, and because the math runs in your browser, an already-open page keeps converting even if your connection drops.
Please report it through the Contact page with the exact numbers and units you used. We treat wrong-result reports as top priority.