Convert length, weight, volume, temperature, area, speed, energy and more.
Length and mass conversions work by expressing the value in a base SI unit (meters or kilograms) and then converting to the target unit. Temperature uses exact Celsius/Fahrenheit/Kelvin formulas. Choose two units of the same category.
Length and mass
result = value × (SI factor for source unit) ÷ (SI factor for target unit)
Temperature: °F ↔ °C
°C = (°F − 32) × 5/9 °F = °C × 9/5 + 32
Temperature: K ↔ °C
K = °C + 273.15 °C = K − 273.15
No — those measure different things (distance vs. mass). Pick two units of the same type: length with length, weight with weight, temperature with temperature.
They use exact internationally-defined factors (e.g. 1 inch = 0.0254 m), so results are accurate to the displayed decimal places.