📐 Math Grades 3–12
Unit Converter
Pick a type of measurement and convert between metric and U.S. customary units. The tool shows the factor it used, so you learn the method too.
Learn How it works
Dimensional analysis (factor-label method): multiply by a fraction equal to 1, with the unit you want on top and the unit you have on the bottom, so the old unit cancels.
5 ft × (12 in / 1 ft) = 60 in · 3.2 km × (1000 m / 1 km) = 3200 m
Metric prefixes: kilo (k) = 1000 · hecto (h) = 100 · deka (da) = 10 · base unit · deci (d) = 0.1 · centi (c) = 0.01 · milli (m) = 0.001. Memory trick: King Henry Died By Drinking Chocolate Milk.
Temperature isn't a simple multiply: °F = °C × 9/5 + 32, and K = °C + 273.15.
Try it Convert
Practice Check yourself
Answer, then tap Check. You get an explanation either way.
30 × 9/5 + 32 = 54 + 32 = 86.