Unit Converter
Convert between US customary and metric units across six categories — length, weight, temperature, volume, area and speed. Results update live as you type.
Every unit in a category is defined by its exact ratio to a base unit — meters for length, kilograms for weight, liters for volume. Converting is a two-step hop: multiply into the base unit, then divide into the target. The factors are the official definitions, so 1 inch is exactly 25.4 millimeters and 1 pound is exactly 0.45359237 kilograms.
Temperature is the exception because its scales have different zero points, not just different sizes. Fahrenheit converts through Celsius: subtract 32, multiply by 5/9. Kelvin shares Celsius’s degree size but starts at absolute zero, 273.15 degrees lower.
Worked examples
Height
A 6-foot person is 72 inches, or 1.8288 meters.
→ 6 ft = 1.83 m
Road trip
A 350-mile drive equals about 563 kilometers.
→ 350 mi ≈ 563.27 km
Cooking
A recipe calling for 2 cups of milk needs about 473 milliliters.
→ 2 cups ≈ 473.18 ml