Celsius to Fahrenheit Converter
Convert temperatures between Celsius and Fahrenheit, with Kelvin. Type in either side.
About this tool
Uses °F = °C × 9/5 + 32 and K = °C + 273.15. Fahrenheit is shown to one decimal place.
Weather apps, oven dials and thermometers do not always agree on units. Type a temperature in Celsius to see Fahrenheit and Kelvin, or type Fahrenheit to get Celsius. Both boxes update as you type, and a short note flags freezing, boiling and body temperature.
How to use the Celsius to Fahrenheit Converter
- Type a temperature in Celsius, for example 25.
- Read the Fahrenheit next to it, and the Kelvin below.
- Or type Fahrenheit instead, and the Celsius updates.
- Negative numbers work too, for cold weather or freezers.
Converting 25 °C and 350 °F
25 × 9/5 = 45, and 45 + 32 = 77, so 25 °C is 77 °F. For an American recipe that says 350 °F: 350 − 32 = 318, and 318 × 5/9 = 176.7, so set the oven to about 180 °C (or 160 °C for a fan oven).
The formula
The two scales have different zero points and different degree sizes. Water freezes at 0 °C and 32 °F and boils at 100 °C and 212 °F at sea level, so 100 Celsius degrees span 180 Fahrenheit degrees. That gives °F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9. Kelvin uses Celsius-sized degrees starting from absolute zero: K = °C + 273.15. The scales meet at −40, where −40 °C equals −40 °F.
Frequently asked questions
What is normal body temperature in Fahrenheit?
About 98.6 °F, which is 37 °C. Normal readings vary a little from person to person.
What is 180 °C in Fahrenheit?
356 °F, a common oven setting.
At what temperature are Celsius and Fahrenheit the same?
At −40, where −40 °C equals −40 °F.
Is there a quick mental shortcut?
Double the Celsius and add 30 for a rough Fahrenheit figure: 20 °C gives about 70 °F (the exact answer is 68 °F).