How to Convert Temperature Measurements

Several different temperature scales exist - the Celsius scale sets freezing and boiling points of water at 0 and 100, respectively, while the Fahrenheit scale sets them at 32 and 212. Here's how to convert between the two types.

Difficulty: Easy

Instructions

Things You'll Need:

• Calculators
• Thermometers
• Paper And Pencils
• Calculators
• Thermometers

1. Multiply the Celsius temperature reading by 9/5, and then add 32 to get the temperature in Fahrenheit: (9/5 * C) + 32 = F.

2. Subtract 32 from the Fahrenheit temperature, and then multiply this quantity by 5/9 to get the temperature in Celsius: (F ' 32) * 5/9 = C.

3. Add 273.15 to the Celsius temperature to get Kelvin temperature (the scale used in thermodynamics calculations). To convert from Fahrenheit to Kelvin temperature, first convert Fahrenheit to Celsius using the formula in step 2, and then add 273.15 to the Celsius temperature.

4. Add 459.6 to the Fahrenheit temperature to get Rankine temperature (a system used by some engineers).

Tips & Warnings

• An easier way to remember temperature conversions is to use estimates, such as 2 for 9/5. For example, multiply temperature in Celsius by 2, and then add 32 to get the approximate temperature in Fahrenheit.

[Korleone]

on 2/19/2008 Forget everything I just said, it's all wrong. It's not 100/212, it's 100/180 which is 5/9. :)

[Korleone]

on 7/10/2007 If remembering 25/53 is taxing you far too much, then remember 8/17. This'll still give you a much close approximation than 5/9. Just for god's sake don't use 5/9. It's in books everywhere, and it's wrong!

25/53
25/53
25/53
!

[Korleone]

on 7/10/2007 Multiplying by 5/9 is lame. Basically, you want to multiply by 100/212. Thing is, most people find this too difficult to remember. Well, 25/53 is the same as 100/212.
5/9 isn't close enough.

For example, convert 150° Fahrenheit to Celsius using the formula on this page will give you 65.5° Celsius. The correct answer with my formula gives you 55.7° Celsius. The 5/9 formula is 10 degree out!
Ridiculous.

Fahrenheit to Celsius:
subtract 32, multiply by 25, divide by 53.