How to Convert Units (Quick Method and Free Converter)
3 min read
Converting between units sounds fiddly, but almost all of it comes down to one trick: multiply by a conversion factor. Temperature is the only one that needs a formula instead.
Here is how to convert units reliably, plus the conversions people look up most.
Step by step
- 1Use a conversion factor
Multiply by how many of the new unit fit in the old one. 1 mile = 1.609 km, so 5 miles x 1.609 = 8.05 km. To go the other way, divide.
- 2Common length and weight
1 inch = 2.54 cm; 1 foot = 0.3048 m; 1 mile = 1.609 km; 1 kg = 2.205 lb; 1 lb = 0.4536 kg; 1 oz = 28.35 g.
- 3Temperature (the exception)
It needs a formula, not a factor: F = C x 9/5 + 32, and C = (F - 32) x 5/9. So 20C = 68F.
- 4Use the converter
Skip the arithmetic — the Unit Converter handles length, weight, temperature, volume and more instantly.
Tips
- To sanity-check, remember the answer should be bigger when converting to a smaller unit (more of them fit).
- A meter is a bit more than a yard; a kilogram is about 2.2 pounds; 100 km/h is roughly 62 mph.
- Round only at the end to avoid compounding small errors.
Frequently asked questions
How do I convert between units?
Multiply by the conversion factor (how many new units equal one old unit). For example, miles to km: multiply by 1.609. Temperature uses a formula instead.
How do I convert Celsius to Fahrenheit?
F = C x 9/5 + 32. So 25C = 25 x 1.8 + 32 = 77F. To reverse: C = (F - 32) x 5/9.
What is 1 kg in pounds?
1 kilogram is about 2.205 pounds. To convert kg to lb, multiply by 2.205; for lb to kg, multiply by 0.4536.