Unit Converter

Convert length, weight, temperature, volume, area and speed with exact international factors — results update live in both directions as you type.

Live — converts as you type

Quick reference

Exact Conversion Factors

This converter uses internationally defined factors — not rounded approximations:

  • 1 inch = exactly 2.54 cm (international yard and pound agreement, 1959)
  • 1 pound = exactly 0.45359237 kg
  • 1 mile = exactly 1.609344 km
  • 1 US gallon = exactly 3.785411784 liters
°F = °C × 1.8 + 32   ·   K = °C + 273.15

Temperature is the only category converted with offset formulas rather than simple multiplication — this tool handles that automatically.

Popular Conversions

  • km ↔ miles: running distances, road trips, flight routes
  • kg ↔ lbs: body weight, luggage allowances, shipping — pair with our BMI Calculator
  • °C ↔ °F: weather, cooking temperatures, fevers
  • liters ↔ gallons: fuel economy, recipes, aquariums
  • m² ↔ ft²: apartments, real-estate listings, flooring

Frequently Asked Questions

How do I convert kilometers to miles?
Multiply km by 0.621371 — e.g. 10 km = 6.21 miles. Miles to km: multiply by 1.60934.
How do I convert kilograms to pounds?
Multiply kg by 2.20462 — e.g. 70 kg = 154.32 lbs. Pounds to kg: multiply by 0.453592.
How do I convert Celsius to Fahrenheit?
°F = °C × 1.8 + 32 — e.g. 25°C = 77°F. Back again: °C = (°F − 32) ÷ 1.8.
Is this converter exact?
Yes — internationally defined factors (1 in = exactly 2.54 cm; 1 lb = exactly 0.45359237 kg), shown to 6 significant decimals.