100°F to °C — What is 100 Fahrenheit in Celsius?

100°F = 37.78°C. Use the exact formula (°F − 32) × 5/9 to convert any Fahrenheit temperature to Celsius — algebraically exact with zero rounding, as defined by the NIST.

Answer

37.78°C

100 °F = 37.78 °C

Exact: 37.780000 °C · uses the BIPM-defined constant

How it's calculated

(°F − 32) × 5/9 = °C

Step 1: Apply the formula to the input value.
Step 2: (100 − 32) × 5/9 = 68 × 5/9 = 37.78

What does 100°F feel like?

100°F is warm to very warm. US heat advisories are typically issued above 90°F with high humidity. Normal body temperature is 98.6°F — 100°F is slightly above or at normal body temperature.

100°F in other temperature scales

Celsius

37.78°C

Fahrenheit

100°F

Kelvin

310.93 K

Common temperature references

Key temperatures from science, cooking, and medicine

°C	°F	Reference
-40°C	-40°F	°C and °F are equal
-18°C	0°F	Zero Fahrenheit
0°C	32°F	Water freezes
10°C	50°F	Cool day
20°C	68°F	Room temperature
25°C	77°F	Warm room
37°C	98.6°F	Body temperature
38°C	100.4°F	Fever threshold (WHO)
100°C	212°F	Water boils (sea level)
160°C	320°F	Low oven
180°C	356°F	Moderate oven (Gas Mark 4)
200°C	392°F	Hot oven (Gas Mark 6)
220°C	428°F	Very hot oven (Gas Mark 7)
250°C	482°F	Max home oven

Fahrenheit to Celsius — Nearby Values

Click any row to open its full conversion page

Fahrenheit (°F)	Celsius (°C)
50 °F	10 °C
60 °F	15.56 °C
65 °F	18.33 °C
70 °F	21.11 °C
75 °F	23.89 °C
80 °F	26.67 °C
85 °F	29.44 °C
90 °F	32.22 °C
95 °F	35 °C
100 °Fthis page	37.78 °C
105 °F	40.56 °C
110 °F	43.33 °C
115 °F	46.11 °C
120 °F	48.89 °C
125 °F	51.67 °C
130 °F	54.44 °C
135 °F	57.22 °C
140 °F	60 °C
145 °F	62.78 °C
150 °F	65.56 °C

Common questions about 100 °F to °C

What is 100°F in Celsius?

100 degrees Fahrenheit equals exactly 37.78 degrees Celsius. The formula is (100 − 32) × 5/9 = 37.78°C. In Kelvin, this is 310.93 K.

How do you convert 100°F to °C step by step?

Step 1: Subtract 32 from 100 to get 68. Step 2: Multiply by 5/9 (or 0.5556). Result: 68 × 5/9 = 37.78°C. This formula is algebraically exact.

Is 100°F hot or cold?

100°F is very hot. Extreme heat conditions — limit outdoor activity.

What is 37.78°C back in Fahrenheit?

37.78°C converts back to exactly 100°F — which is 100°F. The conversion is perfectly reversible using the inverse formula: (°C × 9/5) + 32.

Is 100°F a fever?

The WHO defines fever as body temperature above 100.4°F (38°C). 100°F is within the normal adult range (97–99°F per Stanford Medicine 2020).

What should I wear at 100°F?

At 100°F, extreme heat clothing: lightest possible fabrics, wide-brim hat, frequent water breaks. Avoid outdoor exertion during midday. Seek air-conditioned spaces.