Temperature Conversion

SPREAD from Freezing to Boiling of Water

The Celsius scale spread is approximately 100 degrees between freezing and boiling of water. (The modern and more precise definition of the unit scale of Celsius/Centigrade references absolute zero and a special "triple point" value of water. This puts the boiling of water at 99.9839 °C. But 100 °C is close enough for our application.)

So: 100 °C - 0 °C = 100 degree difference

The Farenheit scale spread is 180 degrees between freezing and boiling of water.

So: 212 °F - 32 °F = 180 degree difference

RATIO

The ratios of this difference can be used to convert between the two unit systems.

100 / 180 ----> 5/9 when converting from °F to °C

CONVERSION °F to °C

°F - 32 = value
value * 5/9 = °C

CONVERSION °C to °F

This formula is the °F to °C formula in reverse:

°C * 9/5 = value
value + 32 = °F