The Celsius and Kelvin scales use the same size degree (“incremental scaling” is the technical term), but set their zero values at different absolute numbers. Let’s explain that sentence a bit more: If you go up by one degree Celsius or one degree Kelvin, you’ve raised the temperature the same amount, but 0 °C (the temperature at which water freezes) is 273.15 K. Thus the two scales are offset from one another by 273.15.

Fahrenheit is completely different though. Water freezes at 32 °F, and a change of one degree on the Fahrenheit scale is equal to a change of 0.55 °C.