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Temperature Conversion: Celsius to Fahrenheit | F to C or C to F | The Old Farmer's Almanac

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Temperature Conversion Formula: Celsius to Fahrenheit

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Find the temperature conversion formula, chart, and calculator!

December 21, 2022
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F to C: Fahrenheit to Celsius Conversion Calculator

Fahrenheit Celsius
°F °C

Enter a value for Fahrenheit or Celsius to convert to the other.

Here’s a temperature conversion formula, chart, AND calculator to change Fahrenheit to Celsius or Celsius to Fahrenheit. Whether you want to understand the math or just want the answer now, you can go from C to F or F to C!

For those who just want an answer, above is our Temperature Conversion Calculator.

The Temperature Conversion Formula

The conversion formulas we use are the standard ones that are used in most textbooks. 

To convert temperatures in degrees Fahrenheit to Celsius, subtract 32 and multiply by .5556 (or 5/9).

  • Example: (50°F - 32) x .5556 = 10°C

To convert temperatures in degrees Celsius to Fahrenheit, multiply by 1.8 (or 9/5) and add 32.

  • Example: (30°C x 1.8) + 32 = 86°F’

Here are two handy charts that convert from F to C and also from C to F.

Fahrenheit to Celsius Conversion Chart

Fahrenheit

Celsius
-40°F -40°C
-30°F -34°C
-20°F -29°C
-10°F -23°C
0°F -18°C
10°F -12°C
20°F -7°C
32°F 0°C
40°F 4°C
50°F 10°C
60°F 16°C
70°F 21°C
80°F 27°C
90°F 32°C
100°F 38°C

Celsius to Fahrenheit Conversion Chart

Celsius

Fahrenheit
-40°C -40°F
-30°C -22°F
-20°C -4°F
-10°C 14°F
0°C 32°F
10°C 50°F
20°C 68°F
30°C 86°F
40°C 104°F
50°C 122°F
60°C 140°F
70°C 158°F
80°C 176°F
90°C 194°F
100°C 212°F

About Fahrenheit and Celsius

The Fahrenheit temperature scale is named for German physicist Daniel Gabriel Fahrenheit and is the measurement of temperature commonly used by the United States (and its associated territories) and by several nations in the Caribbean. On the Fahrenheit scale, water freezes at 32°F and boils at 212°F (at sea level).

The Celsius temperature scale—originally called centigrade and later renamed for Swedish astronomer Anders Celsius—is used almost everywhere else in the world. On the Celsius scale, water freezes at 0°C and boils at 100°C (at sea level).

Other Conversions

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Comments

We looked at comments below and found one comment interesting.  When you convert Fahrenheit to Celsius (as shown above), the last thing you need to do is multiply by 5/9 or .5556. Since 5/9 is only approximately equal to .5556, you do get slightly different answers depending on whether you use 5/9 or .5556. The commenter suggests that instead of multiplying by 5/9 or .5556 that you divide by 9/5 or 1.8. This is because 9/5 is exactly equal to 1.8 and, therefore, you will avoid getting slightly different answers. The only drawback that we see in using this method is that it is not the formula you normally see in textbooks (if that’s a concern).

mike (not verified)

1 month 3 weeks ago

This is much easier:

C->F ADD 40, Divide by 5, Multiply by 9, SUBTRACT 40

F->C ADD 40, Divide by 9, Multiply by 5, SUBTRACT 40

Notes: always ADD 40 first, if you *want Fahrenheit* then you want 'more' range so multiply by 9 (and divide by 5), if you *want Celsius* then you want 'less' range so divide by 9 (and multiply by 5), then SUBTRACT 40

No 32's in sight.

Morris (not verified)

1 month 4 weeks ago

I cannot change the Fahrenheit to Celsius. I use the calculator, it is (37-32) x 0.5556, right

Sean (not verified)

6 months 1 week ago

Multiplying by 5/9? Not exactly "easy" though...

As someone who has to work with both temperature systems, I use this for a quick and easy way to get a number close enough to understand.

For C to F "double it and add 30" so 20 C = (2x20) + 30 = 70F which is close to the real value of 68F to know it's a nice day.

F to C "subtract 30 and halve it" so 100F = (100-30)/2 = 35C which is close to the actual value of 37.8C and getting pretty warm.

It's not perfect, but it is quick and easy enough to do in your head.

Another trick? Remember that:
0C is 32F
16C is 61F, and
28C is 82F.

If the number you want is close to those 3 numbers then just treat 2F = 1C and work it out from there. What is 20C? 16C + 4 = 61F + 8 = 69F which is close enough to 68F for me. What is 26F? 32-26 = 6F or 3C so it's 3C below freezing or -3C.

(Side note, -40C is the same as -40F but by then who cares, that's just seriously cold everywhere...)

Shadab Hussain (not verified)

7 months ago

Useful Information, Helps a lot.