Degrees Fahrenheit to Degrees Celsius Converter

The converter above is already set to degrees Fahrenheit and degrees Celsius, so you only need to enter your number. The result updates as you type, and nothing is sent anywhere.

1. Type your value in the Value box, for example 98.6. Decimals and negative numbers are accepted.
2. Check that From shows degrees Fahrenheit and To shows degrees Celsius. Both menus can be changed if you need a different pair.
3. Read the answer in the large result box. The note under it shows the exact factor used for one degree Fahrenheit.
4. Press Copy result to put the answer on your clipboard, or Swap units to convert in the opposite direction.
5. Look at In every unit on the right to see the same amount in all the other temperature units.

Temperature scales start from different zero points, so the conversion needs an offset as well as a multiplier. The formula is Celsius = (Fahrenheit - 32) x 5/9. The Fahrenheit scale puts the freezing point of water at 32 and its boiling point at 212, and it is used mainly in the United States. The Celsius scale puts the freezing point of water at 0 and its boiling point at 100 at standard pressure.

Worked examples with the same formula:

• 98.6 degrees Fahrenheit: (98.6 - 32) x 5/9 = 37 degrees Celsius
• 212 degrees Fahrenheit: (212 - 32) x 5/9 = 100 degrees Celsius
• 0 degrees Fahrenheit: (0 - 32) x 5/9 = -17.7778 degrees Celsius

Subtract 30 and halve for a rough value, or subtract 32 and multiply by 5/9 for the exact one: 70 F gives 20 C by the shortcut and exactly 21.1 C.

To check the converter by hand, take 212 degrees Fahrenheit and apply the rule once: the result should be 100 degrees Celsius. A reading, not a difference, is what the formula expects, so enter the actual temperature and not the change.

These reference values come from the same factor the converter uses, so they match what you see above. Use the table for common amounts, and the converter for anything else.

Celsius and Fahrenheit differ in both the size of a degree and the position of zero. A Celsius degree is 1.8 times larger than a Fahrenheit degree, and 0 degrees Celsius is 32 degrees Fahrenheit. The two scales agree at exactly minus 40, which makes a handy check: if you convert minus 40 you should get the same number back. Kelvin uses the Celsius step but starts at absolute zero.

Use the table to spot check your result against familiar points. Water freezes at 0 C, 32 F and 273.15 K, and boils at 100 C, 212 F and 373.15 K at standard pressure, while normal body temperature is about 37 C or 98.6 F. If your answer is far from where such a landmark would put it, recheck the unit you selected.

US weather reports, ovens, body temperature at 98.6 F and cooking temperatures need translating for readers who use Celsius.

Be careful with temperature differences. A change of 10 degrees Celsius is a change of 18 degrees Fahrenheit, but a reading of 10 C is 50 F. The offset only applies to readings, not to differences between them.

Related pages: Degrees Celsius to Degrees Fahrenheit Converter for the reverse direction, and the kelvin to degrees celsius and degrees celsius to kelvin pages. For other temperature units use the temperature converter.

The page keeps no history, so each visit starts again from the defaults, 98.6 degrees Fahrenheit. Your numbers are processed by JavaScript in your own browser and are never sent to a server, which makes the converter safe for private figures such as medical, financial or work measurements.