100 Fahrenheit to Celsius
37.8 °C
100 °F = 37.8 °C.
Celsius
37.8°C
100 °F = 37.8 °C
The short answer
How many Celsius is 100 Fahrenheit?
100 °F = 37.8 °C. 1 Fahrenheit = 0.555556 Celsius, then − 17.77777777777778, so the working is 100 × 0.555556 − 17.7778 = 37.8.
The working
The factor below is an exact definition rather than a measurement, so nothing is approximated in the arithmetic. The only rounding on this page happens where a number is displayed.
1 Fahrenheit = 0.555556 Celsius, then − 17.77777777777778 100 × 0.555556 − 17.7778 = 37.8
How much precision do you need?
Each row is the same answer cut at a different number of decimals, with what that choice costs you. Pick the shortest row whose error is smaller than whatever you are measuring with.
| Rounded to | Answer (°C) | Off by |
|---|---|---|
| Whole number | 38 | +0.22222 |
| 1 decimal | 37.8 | +0.02222 |
| 2 decimals | 37.78 | +0.00222 |
Round trip: take 37.8 °C back the other way and you land on 100.0400 °F — a drift of 0.0400 °F. That gap is the rounding, not the conversion.
What 100 °F looks like
100 °F
A temperature of 100.4 Fahrenheit or higher counts as a fever under CDC guidance, whichever way it was measured.
Frequently asked questions
What is 100 Fahrenheit in Celsius?
100 Fahrenheit is 37.8 Celsius. 1 Fahrenheit = 0.555556 Celsius, then − 17.77777777777778, so the working is 100 × 0.555556 − 17.7778 = 37.8.
How accurate is 37.8 °C?
Rounding to 37.8 °C and converting straight back gives 100.0400 °F, a drift of 0.0400 °F from the 100 you started with. The factor itself is exact; every bit of that difference comes from the rounding, not the conversion.
Nearby values
Any value at all
Fahrenheit to Celsius Converter
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