If you live in one of the many countries that use the Celsius temperature scale, you may not be used to dealing in Fahrenheit.
But that doesn’t mean that it doesn’t pop up from time to time, like in recipes or on a trip to the US... or literally anywhere that isn't the US, the Bahamas, the Cayman Islands, Liberia, Palau, the Federated States of Micronesia or the Marshall Islands.
You may have learned how to convert Celsius to Fahrenheit (and vice versa) during your primary school maths class, but there’s a good chance you don’t remember how to do that today. Thankfully, Reddit user quaxon shared a dead-simple method for converting between Celsius and Fahrenheit in your head with no need for a calculator.
The formula to convert between the two temperature scales isn’t something most of us can do in our head, but if you just need a close estimation, quaxon’s formula works well:
C to F: Multiply the temperature by 2 and then add 30
(actual formula is multiply by 1.8, add 32)
ex: 22 C is roughly equal to 74 degrees using my method, actual conversion is 71.6
F to C: Now just work it backwards, subtract 30 from the temp. and then divide by 2
(again, actual formula constants are 1.8 and 32)
As you can see from quaxon’s example it isn’t an exact result, but if you simply need to convert some temperatures when you’re cooking or following other directions it works great in a pinch.