100 Fahrenheit to Celsius
100 °F equals approximately 37.78 °C. Change the value, swap Celsius and Fahrenheit, or copy the result with its formula.
Best solution
Default conversion: 100 °F is approximately 37.78 °C; exact result: 340/9 °C.
Temperature reading · up to 2 decimal places
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Calculation for 100 °F
(100 − 32) × 5/9 = 68 × 5/9 = 340/9 °C = 37.778… °C ≈ 37.78 °C.
The exact result is 340/9 °C. In decimal form, it is approximately 37.78 °C.
For a temperature reading, use °F = °C × 9/5 + 32, or °C = (°F − 32) × 5/9. Results are displayed to at most two decimal places. Negative values are allowed down to −273.15 °C or −459.67 °F (absolute zero). The calculator converts readings, not temperature changes: a change of 1 °C is a change of 1.8 °F, with no 32-degree offset. NIST temperature conversion reference.
Changing the input updates the calculator only; the worked example below it stays on the value named in this page. Swap uses the displayed, rounded result as the next input, so repeated swaps may introduce a small rounding difference. Unit conversion does not determine a diagnosis or a recommended device setting.
Real-World Context & Technical Standards
Fever Threshold on Fahrenheit Scale
100.0 °F (37.78 °C) is the common clinical threshold where body temperatures transition from normal fluctuation to low-grade fever status.
Triple-Digit Summer Heatwave Benchmark
A 100 °F day is celebrated or dreaded across the American South and West as a 'triple-digit day,' triggering heat health advisories.
Related conversions
Frequently Asked Questions
How do I convert 100 °F to °C?
(100 − 32) × 5/9 = 68 × 5/9 = 340/9 °C = 37.778… °C ≈ 37.78 °C.
Is 37.78 °C exact or rounded?
The exact result is 340/9 °C. In decimal form, it is approximately 37.78 °C.