Celsius to Fahrenheit converter
Enter a value in either field and get the conversion instantly.
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How it works
- 1
Pick a field
Type the temperature in Celsius, or directly in Fahrenheit — whichever you have.
- 2
Read the conversion
The other field updates automatically, no button required.
- 3
Use the result
Apply it to weather, body temperature, or oven recipes given in imperial units.
How to convert Celsius to Fahrenheit
The exact formula is F = C × 9/5 + 32: multiply the Celsius temperature by 9/5 (1.8) and add 32. For example, 25 °C × 1.8 + 32 = 77 °F. Going the other way uses C = (F − 32) × 5/9: subtract 32 from the Fahrenheit value and multiply the result by 5/9. Unlike kg/lb or cm/in, this isn't a simple multiplication — it's an affine relationship, because the Celsius and Fahrenheit scales have different zero points (0 °C = 32 °F).
This conversion comes up constantly when reading the weather in the US (which uses Fahrenheit), when interpreting body temperature on an imported thermometer (37 °C ≈ 98.6 °F is normal body temperature), or when following oven recipes in imperial units, where 180 °C is 356 °F.
Frequently asked questions
What's a quick mental shortcut from Celsius to Fahrenheit?
Double the Celsius value and add 30 for a rough estimate (e.g. 20 °C × 2 + 30 = 70 °F, close to the exact 68 °F). For precise results, use the exact formula F = C × 9/5 + 32.
At what temperature are Celsius and Fahrenheit equal?
At −40 degrees: −40 °C equals exactly −40 °F, the only point where both scales meet.
What's normal body temperature in Fahrenheit?
37 °C (average body temperature) equals 98.6 °F. A 38 °C fever is 100.4 °F.
Why does water boil at 100 °C but 212 °F?
Both scales measure the same thing with different reference points: Celsius sets 0° at water's freezing point and 100° at boiling, while Fahrenheit sets those same points at 32° and 212°.