Convert Fahrenheit to Celsius Part I

< Previous Lesson | Measurement Lessons | Next Lesson >

Temperature Conversion: Learn

The metric system uses the Celsius scale to measure temperature. However, temperatures are still measured on the Fahrenheit scale in the U.S.

Water freezes at 0° Celsius and boils at 100° Celsius, which is a difference of 100°. Water freezes at 32° Fahrenheit and boils at 212° Fahrenheit, which is a difference of 180°. Therefore each degree on the Fahrenheit scale is equal to 100/180 or 5/9 degrees on the Celsius scale.

How to convert Fahrenheit temperatures to Celsius:

Subtract 32° to adjust for the offset in the Fahrenheit scale.
Multiply the result by 5/9.

Example: Convert 98.6°F to Celsius

98.6 - 32 = 66.6
37 * 9/5 = 333/5 = 66.6
66.6 + 32 = 98.6°F

There is a mental math method to approximate the Fahrenheit to Celsius conversion. The ratio of 5/9 is approximately equal to 0.55555....

How to approximately convert Fahrenheit temperatures to Celsius with mental math:

Subtract 32° to adjust for the offset in the Fahrenheit scale.
Divide the difference by 2 (multiply by 0.5)
Take one-tenth of that quotient (0.5 * 1/10 = 0.05) and add it to the quotient

Example: Convert 98.6°F to Celsius

98.6 - 32 = 66.6
66.6 / 2 = 33.3
33.3 * 1/10 is approximately 3.3, so 36.6+3.3 = 39.6°C

Converting Temperature: Practice

Convert and round to the nearest degree.

00:00

°F

°C

Press the Start Button To Begin

You have 0 correct and 0 incorrect.

This is 0 percent correct.

Play

Game Name	Description	Best Score
	How many correct answers can you get in 60 seconds?	0
	Extra time is awarded for each correct answer. Play longer by getting more correct.	0
	How fast can you get 20 more correct answers than wrong answers?	999