About the Fahrenheit to Celsius
This Fahrenheit to Celsius converter changes any temperature in degrees Fahrenheit (°F) into degrees Celsius (°C) and kelvin. Enter a whole number, a decimal or a negative value and the result appears straight away, along with the formula filled in with your own number.
Use it to understand a US weather forecast, convert an American recipe or oven temperature for a metric oven, read a fever on a Fahrenheit thermometer, or check lab and homework answers. The reference table lists the conversions people search for most often, from freezing winter days to baking temperatures.
The conversion is exact because the Fahrenheit scale is defined in terms of the Celsius scale. For a rough mental estimate, subtract 30 and halve the result — but use the calculator when precision matters, such as for cooking or medical readings.
With the default inputs, the celsius is 21.11 °C. Change any value above to recalculate instantly.
How to use the fahrenheit to celsius
- 1Enter the temperature in degrees Fahrenheit.
- 2Read the Celsius result and the kelvin equivalent.
- 3Check the working line to see (°F − 32) × 5/9 with your number.
- 4Scan the table for common oven, weather and body temperatures.
Formula and method
First subtract 32, because water freezes at 32 °F but at 0 °C — this lines up the zero points of the two scales. Then multiply by 5/9 (about 0.5556), because a Celsius degree is 1.8 times larger than a Fahrenheit degree.
Kelvin is Celsius shifted to start at absolute zero, so K = °C + 273.15. Both conversions are exact; the only rounding is in the decimals displayed.
- °F
- Temperature in degrees Fahrenheit
- °C
- Temperature in degrees Celsius
- K
- Temperature in kelvin (°C + 273.15)
Worked examples
Fever check: 98.6 °F
98.6 − 32 = 66.6, and 66.6 × 5/9 = 37 °C, the classic normal body temperature. Adding 273.15 gives 310.15 K.
Baking at 350 °F
350 − 32 = 318, and 318 × 5/9 ≈ 176.7 °C. Metric recipes usually round this to 180 °C (or 160 °C for a fan oven).
A freezing 0 °F winter day
0 − 32 = −32, and −32 × 5/9 ≈ −17.8 °C — well below the freezing point of water.
Frequently asked questions
What is the formula for Fahrenheit to Celsius?+
Subtract 32 from the Fahrenheit temperature, then multiply by 5/9. For example, 68 °F − 32 = 36, and 36 × 5/9 = 20 °C.
How do I convert Fahrenheit to Celsius in my head?+
Subtract 30 and divide by two. 80 °F becomes (80 − 30) ÷ 2 = 25 °C, close to the exact 26.7 °C. The shortcut is fine for weather but not for cooking or medicine.
What is 100 °F in Celsius?+
100 °F is about 37.8 °C. As a body temperature it is slightly raised, just under the 100.4 °F (38 °C) level commonly used to define a fever; as an air temperature it is a very hot day.
What is 350 °F in Celsius for baking?+
350 °F is 176.7 °C, usually written as 180 °C in metric recipes. With a fan (convection) oven, reduce to about 160 °C.
Why does the US use Fahrenheit?+
Fahrenheit was the standard in the British Empire when the US was founded. Most countries switched to Celsius during metrication in the 20th century, but the US kept Fahrenheit for everyday use.