Free Unit Converter — All Measurement Categories
Our Unit Converter covers all six major measurement categories — length, weight (mass), temperature, volume, area, and speed. Whether you're converting miles to kilometers for a road trip, kilograms to pounds for a recipe, or Celsius to Fahrenheit for a weather report, this tool provides instant, accurate results with the conversion formula shown.
All conversions are based on official SI (International System of Units) definitions and US/UK customary unit standards. Results are calculated to full floating-point precision.
Last Updated: April 2026
Frequently Asked Questions
Multiply by 9/5 then add 32: °F = (°C × 9⁄5) + 32. Example: 0°C = 32°F, 100°C = 212°F, 37°C (body temp) = 98.6°F.
There are exactly 5,280 feet in 1 mile. 1 mile = 1,760 yards = 5,280 feet = 63,360 inches = 1.60934 kilometers.
1 ounce (oz) = 28.3495 grams. 1 pound = 16 ounces = 453.592 grams. 1 kilogram = 35.274 ounces.
1 US gallon = 3.78541 liters. 1 UK (Imperial) gallon = 4.54609 liters. UK gallons are about 20% larger than US gallons. Always check which gallon system is being used in recipes.
100 km/h = 62.14 mph. The conversion factor is 1 km/h = 0.621371 mph. Speed limits in the UK and US are given in mph; most of Europe uses km/h.