Fahrenheit to Celsius Converter
Type in either box to convert F to C temperature instantly, both ways.
Runs entirely in your browser. Nothing you type is uploaded.
How to use this tool
This Fahrenheit to Celsius converter has two linked inputs. Type a number into the Fahrenheit box and the Celsius box updates live, and the same works the other way around. Use the Swap units button to flip the two values, which is handy as a quick imperial metric heat toggle, and Clear to reset both fields. Decimals are allowed, so 98.6 or 72.5 work fine.
The formula
To convert Fahrenheit to Celsius you subtract 32, then multiply by five ninths. To go back from Celsius to Fahrenheit you multiply by nine fifths and add 32. The two scales meet at exactly minus 40 degrees, where Fahrenheit and Celsius read the same number.
A real example
Say a recipe lists an oven at 350 degrees Fahrenheit and you have a metric oven. Subtract 32 to get 318, multiply by 5 to get 1590, then divide by 9. That gives about 176.7 degrees Celsius, which most people round to 175 on the dial. Going the other way, normal body temperature of 37 degrees Celsius becomes 37 x 9 / 5 + 32, which is 98.6 degrees Fahrenheit.
Common temperatures for reference
| Description | Fahrenheit | Celsius |
|---|---|---|
| Water freezes | 32 °F | 0 °C |
| Cold winter day | 14 °F | -10 °C |
| Room temperature | 68 °F | 20 °C |
| Warm day | 86 °F | 30 °C |
| Body temperature | 98.6 °F | 37 °C |
| Hot summer day | 104 °F | 40 °C |
| Water boils | 212 °F | 100 °C |
Common questions
What is the quick formula for Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit value, then multiply the result by 5 and divide by 9. In short, C equals (F minus 32) times five ninths.
Is there a simple way to estimate in my head?
For a rough answer, subtract 30 from the Fahrenheit number and halve it. For 70 degrees Fahrenheit that gives about 20 degrees Celsius, which is close to the exact 21.1 and good enough for everyday weather.
At what temperature are Fahrenheit and Celsius equal?
They are equal at minus 40 degrees. Minus 40 Fahrenheit and minus 40 Celsius are the same physical temperature, which is the one point where the two scales cross.
Does this temperature conversion work on my phone?
Yes. The layout reflows for phones, tablets, and desktops, and the tool runs fully in your browser, so it works the same on any device with no internet connection needed after the page loads.
How many decimal places does it show?
Results are rounded to two decimal places and trailing zeros are trimmed, so a clean value like 37 stays 37 rather than showing 37.00.