Fahrenheit, Celsius and Kelvin are scales used to measure temperature. Used in the United States, Fahrenheit is based on a scale that recognises 0 degrees C as the freezing point of water and 100 degrees C as its boiling point. Convert Fahrenheit degrees to Celsius with an online converter or temperature chart, or calculate the equivalent Celsius temperature with a formula. On the Celsius scale, 0 is freezing and 100 is the boiling point for water.
Subtract 32 from the temperature in Fahrenheit. For example, if your body temperature is 37 degrees Celsius and you subtract 32, the result is 66.6.
Divide the new total by 9. When you divide 66.6 by 9, the result is 7.4.
Multiply the new total by 5. If you multiply 7.4 by 5, the result is 37. This number is the equivalent temperature in Celsius, 37 degrees.
Reverse the steps to convert Celsius back to Fahrenheit. Multiply the Celsius temperature by 9, divide the result by 5 and add 32 to the total. That gives you the temperature in Fahrenheit.