Unit Converter
Pick a category, type a value and see it converted into every unit at once: length, weight, temperature, volume, area and speed.
How to convert units
- Choose a category: length, weight, temperature, volume, area or speed.
- Type a value and pick the units to convert from and to.
- The main result and every other unit in the category update instantly. Use Swap units to reverse the direction.
Features
Six categories
Length, weight, temperature, volume, area and speed.
All units at once
See the value in every unit, not just one.
Precise
Uses exact international conversion factors.
Private
Conversion runs in your browser; nothing is uploaded.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32: °F = °C × 9/5 + 32. So 20 °C is 68 °F. To go back, subtract 32 and multiply by 5/9.
Are US and UK gallons different?
Yes. A US gallon is 3.785 litres; an imperial (UK) gallon is 4.546 litres. Both appear in the volume category and are labelled.
How accurate are the conversions?
Factors are the exact international definitions (for example 1 inch = 25.4 mm, 1 lb = 0.45359237 kg). Results are shown to 10 significant digits.
What is Mach in the speed converter?
Mach 1 is the speed of sound, taken here as 340.29 m/s at sea level and 15 °C. The real value changes with temperature and altitude.