Temperature converter
Type a temperature, choose the scale, and see the reading in all four scales at once. The formulas are exact; 0 °C is 273.15 K and 32 °F.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Type a temperature. Negative values and a dot or a comma as the decimal separator both work.
- Choose the scale you have and the scale you need. The ⇄ button swaps them.
- The table below shows the reading on all four scales at once.
The converter turns every reading into kelvins and then into the target scale, so all pairs agree.
| From |
To |
Formula |
| °C |
°F |
°F = °C × 9/5 + 32 |
| °F |
°C |
°C = (°F − 32) × 5/9 |
| °C |
K |
K = °C + 273.15 |
| K |
°C |
°C = K − 273.15 |
| °F |
°R |
°R = °F + 459.67 |
| K |
°R |
°R = K × 9/5 |
Worked example
A recipe says 180 °C. In Fahrenheit that is 180 × 9/5 + 32 = 324 + 32 = 356 °F. A US recipe calling for 350 °F is (350 − 32) × 5/9 = 176.7 °C, so a 180 °C fan setting is close enough.
Reference points
- Absolute zero: 0 K = −273.15 °C = −459.67 °F
- Water freezes at 0 °C = 32 °F and boils at 100 °C = 212 °F, at standard atmospheric pressure
- Normal body temperature is conventionally given as 37 °C = 98.6 °F
- A comfortable room: 20 °C = 68 °F
- −40 °C = −40 °F
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 (1.8) and add 32. For example, 25 °C × 1.8 + 32 = 77 °F.
How do I convert Fahrenheit to Celsius?
Subtract 32, then multiply by 5/9. For example, (350 °F − 32) × 5/9 = 176.7 °C, a common oven setting.
At what temperature are Celsius and Fahrenheit equal?
At −40. Put −40 into either formula and you get −40 back.
What is Kelvin and why does it have no degree sign?
Kelvin is the SI unit of temperature. It starts at absolute zero, so it has no negative values, and by convention it is written K rather than °K. A step of 1 K equals a step of 1 °C.
Does this convert temperature differences too?
No. It converts a reading on one scale to a reading on another. A difference of 10 °C is a difference of 18 °F (10 × 9/5), without the +32, so convert differences by hand using the ratio only.