Convert between common units instantly
Convert between metric and imperial units across length, weight, temperature, volume, speed, and area — type a value on either side and the other updates instantly. All conversions run locally in your browser with standard reference factors.
No unit lookup tables, no hunting for the right factor: you see enough decimal places to re-use the result in further calculations.
A European recipe calls for an oven at 180 °C and 250 g of flour. Select temperature, enter 180 — that's 356 °F, so set your oven to 350. Switch to weight, enter 250 g — about 8.8 oz. Temperature is the one conversion that isn't a simple multiplication: °F = °C × 9/5 + 32, which is why 0 °C lands at 32 °F rather than 0.
The US and imperial (UK) systems define them differently: a US cup is 236.6 ml, a metric cup is 250 ml, and US vs. imperial fluid ounces differ by about 4%. For anything precision-sensitive, weight in grams beats volume every time.
In everyday use pounds measure weight and kilograms measure mass, and on Earth's surface the conversion 1 kg ≈ 2.2046 lb holds. The distinction only matters in physics contexts — for cooking, shipping, and body weight, convert freely.
The definitions are exact by international agreement — an inch is exactly 25.4 mm, a pound exactly 0.45359237 kg. Any rounding you see is display precision, not uncertainty in the factor.
Double the Celsius number and add 30. It's within a few degrees across the everyday range (the exact rule is ×1.8 + 32) — good enough for a weather forecast, not for an oven calibration.