Fahrenheit to Celsius Converter
Type a Fahrenheit value and get the exact Celsius equivalent using (F - 32) x 5/9. The tool also shows the Kelvin value by adding 273.15 after the Celsius conversion, so it covers everyday checks and science notes in one pass.
How the conversion works
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1
Enter the Fahrenheit value
Type the temperature in degrees Fahrenheit. Decimals and negatives are fine, down to absolute zero.
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2
Apply the formula
The converter computes `(F - 32) x 5/9` — subtract the offset, then scale by 5/9.
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3
Read the Celsius result
The output keeps enough decimal places for weather, recipes and body-temperature checks.
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4
Use Kelvin when needed
The result summary also includes Kelvin, calculated as `C + 273.15`.
Temperature reference points
Keeping a handful of anchor temperatures in memory is faster than running the formula for everyday numbers.
Anchor table
| Fahrenheit | Celsius | Context |
|---|---|---|
| -40 °F | -40 °C | The scales intersect at this value. |
| 0 °F | -17.78 °C | A very cold winter reading. |
| 32 °F | 0 °C | Water freezes. |
| 68 °F | 20 °C | Comfortable room temperature. |
| 98.6 °F | 37 °C | Typical human body temperature. |
| 100.4 °F | 38 °C | Common fever threshold. |
| 212 °F | 100 °C | Water boils at sea level. |
| 350 °F | 177 °C | Moderate oven in US recipes. |
| 375 °F | 190 °C | Common baking and roasting setting. |
| 450 °F | 232 °C | High heat for pizza and searing. |
Mental shortcuts
- Quick from F: subtract 32, halve, add about 10% back. Close enough for conversation.
- Quick from C: double it and add 30. Within a few degrees over common ranges.
- Same number: at -40, F = C. The only point where the two scales agree.
Precision you actually need
- Weather: one decimal place is plenty; whole degrees are fine.
- Cooking: round oven temperatures to the nearest 5 or 10 °C; the thermostat is not more accurate than that anyway.
- Medical: one decimal is standard; 38.3 °C and 38.5 °C are meaningfully different.
- Scientific: keep the formula exact; do not pre-round the inputs.
Frequently Asked Questions
5/9 is the exact ratio; 0.5556 is the rounded decimal. Using the fraction avoids accumulated rounding error when you chain conversions. For everyday work the decimal is fine; for scientific notes keep the fraction.
Yes. The formula is linear, so -40 F and 32 F both map correctly. Negative Celsius results appear with a minus sign.
Kelvin is Celsius plus 273.15. This tool shows Kelvin in the result summary after converting Fahrenheit to Celsius, so you can copy all three values together.
Nothing about the value you enter is kept — the conversion is computed for the request and then the data is discarded.
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