Unit Converter
Convert length, weight and temperature units instantly.
Something not working, or a feature missing?Report a problem or suggest a tool
How to Use
- 1Choose a category (length, weight or temperature).
- 2Enter a value and select units.
- 3View the converted result instantly.
Features
- Length: mm, cm, m, km, in, ft, yd, mi
- Weight: mg, g, kg, oz, lb
- Temperature: °C, °F, K
Example
Input
10 km
Output
6.21 mi
Convert between common length, weight and temperature units instantly, entirely in your browser.
Length, weight and temperature
Pick a category, enter a value and choose the units to convert between. Length covers millimetres to miles, weight covers milligrams to pounds, and temperature covers Celsius, Fahrenheit and Kelvin. The conversion factors are the exact international definitions, such as 1 inch = 2.54 cm and 1 pound = 0.45359237 kg, so results are as precise as the numbers you type in.
Handy reference
| From | To | Multiply by |
|---|---|---|
| inches | centimetres | 2.54 (exact) |
| feet | metres | 0.3048 (exact) |
| miles | kilometres | 1.609344 (exact) |
| kilometres | miles | ≈ 0.6214 |
| pounds | kilograms | 0.45359237 (exact) |
| kilograms | pounds | ≈ 2.2046 |
| ounces | grams | ≈ 28.35 |
Temperature is different
Temperature scales do not share a zero point, so you cannot convert them by multiplying alone. Celsius to Fahrenheit is °F = °C × 9/5 + 32, and Kelvin is K = °C + 273.15. A few reference points help sanity-check results:
| °C | °F | K | |
|---|---|---|---|
| Water freezes | 0 | 32 | 273.15 |
| Room temperature | 20 | 68 | 293.15 |
| Body temperature | 37 | 98.6 | 310.15 |
| Water boils (sea level) | 100 | 212 | 373.15 |
| Celsius and Fahrenheit meet | −40 | −40 | 233.15 |
Quick mental estimates
- Kilometres to miles: multiply by 6 and divide by 10 (100 km ≈ 60 mi).
- Kilograms to pounds: double it and add 10% (70 kg ≈ 154 lb).
- Celsius to Fahrenheit: double it and add 30 (25 °C ≈ 80 °F; exact is 77 °F).
Height in feet and inches? Convert the feet to inches first (5 ft 9 in = 69 in), then convert inches to centimetres: 69 × 2.54 = 175.26 cm.