Degrees Fahrenheit to degrees Celsius
Type a value in degrees Fahrenheit to see it in degrees Celsius straight away, or type in the second box to convert back.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Type the value in the degrees Fahrenheit box.
- Read the result in degrees Celsius as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
°C = °F × 0.5555555556 − 17.77777778
Multiply by 0.5555555556, then subtract 17.77777778, because the two scales have different zero points.
Example
To convert 25 °F to degrees Celsius: 25 × 0.5555555556 − 17.77777778 = -3.88889 °C.
Conversion table
| Degrees Fahrenheit (°F) | Degrees Celsius (°C) |
|---|---|
| -40 | -40 |
| -20 | -28.8889 |
| -10 | -23.3333 |
| 0 | -17.7778 |
| 10 | -12.2222 |
| 20 | -6.66667 |
| 25 | -3.88889 |
| 30 | -1.11111 |
| 37 | 2.77778 |
| 40 | 4.44444 |
| 50 | 10 |
| 100 | 37.7778 |
About the units
- Degree Fahrenheit
- The scale used in the United States, defined exactly by °F = °C × 9/5 + 32. Water freezes at 32 °F and boils at about 212 °F.
- Degree Celsius
- A degree Celsius is the same size as a kelvin, but the scale is shifted so that K = °C + 273.15 exactly. Water freezes at 0 °C and boils at about 100 °C at standard pressure.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
What is 0 degrees Fahrenheit in degrees Celsius?
0 °F = -17.7778 °C. The formula is °C = °F × 0.5555555556 − 17.77777778.
How do I convert degrees Fahrenheit to degrees Celsius?
Use °C = °F × 0.5555555556 − 17.77777778. For example, 25 °F = -3.88889 °C.
How many degrees Fahrenheit are in one degree Celsius?
1 °C = 33.8 °F.
Why is temperature conversion not a simple multiplication?
Celsius and Fahrenheit do not start at absolute zero, so converting needs an offset as well as a factor. For example °F = °C × 9/5 + 32, which is why 0 °C is 32 °F, not 0.
At what temperature are Celsius and Fahrenheit equal?
At minus 40: -40 °C is exactly -40 °F.