I've always calculated in Celsius, so I don't know any better. In science they use the scale of Kelvin, which is basically the same scale as Celsius, bot only with the zero point moved to the point of molecule standstill, which is the coldest temperature possible. That is approx -273 Celsius. This being said 0 Celsius is approx 273 Kelvin and 100 Celsius is thus approx 373 Kelvin.
Now what is nice to know is that on the original scale as Anders Celsius invented it the scale was reversed. 100 was the freezing point and 0 the boiling point, so the higher the number the colder it became. However after the death of Anders Celsius his friend biologist Carl Lineus switched them and so the current version of the Celsius scale came to be.