Precision unit conversion
Celsius, Fahrenheit and Kelvin all measure the same thing but start counting from different points. Celsius and Fahrenheit are the two you'll hit day-to-day (weather, ovens, health), while Kelvin turns up in science because it starts at absolute zero.
Celsius sets 0° at the freezing point of water and 100° at boiling point. Fahrenheit sets freezing at 32° and boiling at 212°, which is why the conversion isn't a simple multiplication — it needs an offset as well as a scale factor. Kelvin uses the same size "degree" as Celsius but starts at absolute zero (−273.15°C), so converting between the two is just addition or subtraction.
Celsius to Fahrenheit: °F = (°C × 9/5) + 32. Fahrenheit to Celsius: °C = (°F − 32) × 5/9. Celsius to Kelvin: K = °C + 273.15. Kelvin to Celsius: °C = K − 273.15.
| Convert | Result |
|---|---|
| 0°C (freezing) | 32°F / 273.15 K |
| 20°C (room temp) | 68°F |
| 37°C (body temp) | 98.6°F |
| 100°C (boiling) | 212°F / 373.15 K |
| −40°C | −40°F (the crossover point) |
| 180°C (Gas Mark 4) | 356°F |
The full converter switches instantly between Celsius, Fahrenheit and Kelvin — useful for weather, cooking, health readings and science homework alike.
Open Temperature converter →Multiply by 9/5 and add 32. So 20°C is 68°F, and 100°C (boiling point of water) is 212°F.
−40° is the same value on both scales — it's the one point where the two lines cross.
Subtract 32, then multiply by 5/9. For example, 98.6°F (normal body temperature) works out to 37°C.
Kelvin is an absolute scale, not a relative one — it's written as "K", not "°K", because zero Kelvin represents an actual physical limit (absolute zero) rather than an arbitrary reference point like water freezing.
For a straight Celsius/Fahrenheit conversion, this page is fine. For UK Gas Mark specifically, use the dedicated Oven Temperature & Gas Mark converter, since Gas Mark doesn't follow a simple linear formula.