Convert length, weight, temperature and more.
Converting units accurately
This converter changes values between common units of length, weight, temperature, area, volume and speed. Every conversion multiplies by a fixed factor, except temperature, which also needs an offset.
Reference values worth knowing
- 1 inch = 2.54 centimetres (exact)
- 1 mile = 1.609344 kilometres (exact)
- 1 kilogram = 2.20462 pounds
- 1 litre = 0.264172 US gallons
- Celsius to Fahrenheit: F = C × 9 ÷ 5 + 32. So 37 °C = 98.6 °F.
Worked example
To convert 5 feet 9 inches to centimetres, first change everything to inches: 5 × 12 + 9 = 69 inches. Then 69 × 2.54 = 175.26 cm.
Common mistakes
- Mixing US and imperial gallons or pints. They are different sizes.
- Forgetting that a fluid ounce measures volume while an ounce measures weight.
- Rounding too early. Keep extra decimals until the final answer.
Frequently asked questions
Why is temperature different from other units?
Celsius and Fahrenheit have different zero points as well as different step sizes, so a simple multiplication is not enough.