Converting Celsius to Fahrenheit in your head easily.

Questions and answers on how to convert things from one unit or system to another


Converting Celsius to Fahrenheit in your head easily.

Postby Ken Chevy » Tue Sep 27, 2005 10:49 am

Double the celsius number and subtract 10 % then add 32 and you have how many degrees fahrenheit it is.

I subtract the 10% from the doubled number after adding the 32 to it, I find that is easier to do in my head. Lots easier for me than the multiplying by 9/5 and adding 32.

Try a couple in your head, example:

20C = 20+20=40-4 (the 10%) =36+32= 68F

25C = 25+25=50-5=45+32=77F

33C = 33+33=66-6.6=59.4+32=91.4F

1C = 1+1=2-.2=1.8+32=33.8F

I find it easier to subtract the 10% of the 1st part after I add the 32, so in my head the last example would be 1+1=2+32=34-.2=33.8F

or 41+41+32=114-8.2=105.8F

Anyone else have a way to do it in their head beside the 9/5 way? If so, I would like to give it a try without pencil and paper too.
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Ken Chevy
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Postby Guest » Tue Sep 27, 2005 6:04 pm

I'm not sure it is easier. Some people like the formula
F + 40 = 1.8*(C + 40), which is based on -40 F = -40 C.

Add 40 to the Celsius temperature
Use doubling, less 10% for the 1.8 factor
Subtract 40

Postby Guest » Wed Sep 28, 2005 1:25 pm

63 +40
126 double
113.4 -12.6
73.4 -40

Yes, that works too fairly easily in my head. Thanks.

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