The Celsius to Fahrenheit formula
To convert Celsius to Fahrenheit, multiply by 9/5 (1.8) and add 32: °F = °C × 9/5 + 32. For example, 100 °C × 9/5 + 32 = 212 °F, where water boils. To reverse it, use the Fahrenheit to Celsius calculator.
The 32 comes from the offset between the two scales at freezing point, and the 9/5 from the fact that a Celsius degree is 1.8 times as large as a Fahrenheit degree. That is why you must multiply before adding: doing it the other way round gives the wrong answer for every value except one.
How to convert °C to °F
Enter a temperature in Celsius and the calculator multiplies by 9/5 and adds 32 to give Fahrenheit. Use it for weather, cooking, and travel. Negative Celsius values work too — −40 °C equals −40 °F.
Handy anchors for everyday use: 20 °C is 68 °F, a comfortable room; 30 °C is 86 °F, a hot summer day; 180 °C is 356 °F, a standard baking oven; and −18 °C is 0 °F, roughly a home freezer. A temperature difference converts differently from a temperature reading — a 5 °C rise is a 9 °F rise, with no 32 added.
Once that is settled, the celsius to kelvin calculator takes care of the next part.
Celsius to Fahrenheit reference table
| Celsius | Fahrenheit |
|---|---|
| 0 °C | 32 °F |
| 37 °C | 98.6 °F |
| 100 °C | 212 °F |
| −40 °C | −40 °F |
For the same task from a slightly different angle, try the kelvin to celsius calculator.
Frequently asked questions
- What is 100 Celsius in Fahrenheit?
- 100 °C equals 212 °F (100 × 9/5 + 32).
- What is the Celsius to Fahrenheit formula?
- °F = °C × 9/5 + 32 (or °C × 1.8 + 32).
- What is normal body temperature in Fahrenheit?
- 37 °C, which is 98.6 °F.
- How do I convert Fahrenheit back to Celsius?
- Subtract 32 and multiply by 5/9, or use the Fahrenheit to Celsius calculator.
- Is the "double it and add 30" trick accurate?
- It is close but always a little high, because it uses a factor of 2 instead of 1.8. At 20 °C the shortcut gives 70 °F while the true answer is 68 °F, and the gap widens as temperatures rise — at 40 °C it is off by 6 degrees.