@Matt, yes I do.
That makes it simple to convert between the two.
Converting from Fahrenheit to Celsius is much more complicated because not only are the zero points different, the size of the degree is, as well.
There is (was, really) a scale starting at absolute zero but sized in Fahrenheit degrees (where the difference between freezing and boiling is 180 units, rather than a hundred), it was called the Rankine scale. Freezing was 491.67 on that scale.
