Unit Converter
Convert between length, weight, and temperature units — cm to inches, kg to pounds, Celsius to Fahrenheit. A free online unit converter that runs instantly in your browser.
Pick a category, choose your source and target units, and get the converted value instantly — no need to remember conversion factors or hunt down a formula. Each result also shows the rate in both directions, so you can reuse the factor elsewhere.
How to convert units
- Choose a category. Pick Length, Weight, or Temperature. The unit lists update to match.
- Enter a value and pick the units. Type the amount, then choose what you are converting from and to. Use the swap button to reverse the direction without retyping.
- Read the result and the rate. The converted value appears instantly, along with the conversion rate in both directions — useful when you need the factor rather than a single answer.
Common conversions at a glance
| 1 centimetre | 0.393701 inch |
|---|---|
| 1 inch | 2.54 centimeter |
| 1 metre | 3.28084 foot |
| 1 kilometre | 0.621371 mile |
| 1 mile | 1.609344 kilometer |
| 1 kilogram | 2.204624 pound |
| 1 pound | 0.453592 kilogram |
| 1 gram | 0.035274 ounce |
| 1 ounce | 28.3495 gram |
Temperature works differently from the rest. Length and weight convert by multiplying by a fixed factor, but the temperature scales have different zero points, so Celsius to Fahrenheit is (°C × 9/5) + 32 and Fahrenheit to Celsius is (°F − 32) × 5/9. Kelvin shares Celsius's degree size and simply shifts by 273.15.
Frequently asked questions
Which unit categories can I convert?
Length, weight, and temperature. Length covers millimetres through to miles, weight covers milligrams through to tonnes, and temperature covers Celsius, Fahrenheit, and Kelvin — so the common pairs like metres to feet, kilograms to pounds, and Celsius to Fahrenheit are all there.
How accurate are the conversions?
The factors are the internationally defined ones — an inch is exactly 2.54 cm and a mile is exactly 1609.344 m, so those conversions are exact. Pound and ounce use the standard avoirdupois factors rounded to six significant figures, which is well inside everyday and trade tolerances. Results are displayed rounded for readability, so for metrology or laboratory work, check the displayed precision against what your task requires.
Can I convert between metric and imperial units?
Yes, in both directions — centimetres to inches and inches to centimetres, kilograms to pounds and pounds to kilograms. The swap button reverses the direction without retyping the value.
How many centimetres are in an inch?
Exactly 2.54 cm, by international definition since 1959. So 12 inches is 30.48 cm, and 1 cm is about 0.3937 inches.
How do I convert kilograms to pounds?
Multiply by about 2.20462 — so 70 kg is roughly 154.3 lb. Going the other way, divide by the same figure, or multiply pounds by about 0.4536 to get kilograms.
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32: 20°C is 68°F. Temperature is the one category that needs a formula rather than a multiplier, because the two scales have different zero points — which is also why 0°C is 32°F, not 0°F.