Not only are Celsius and Fahrenheit degrees different sizes (each Celsius degree covers more of the scale) they have different baselines. Fortunately, there are easier ways to convert temperatures ...

His competing scale measured temperature according to its impact on water, which freezes at 0C and boils at 100C. To convert from Fahrenheit to Celsius, simply subtract 32 and multiply by 0.5556 ...

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 ...