Temperature converters

Temperature is the only common everyday measurement that requires an affine conversion — a multiplication and an additive offset — because the zero points of different scales are deliberately different. Kelvin's zero is absolute zero; Celsius's zero is the freezing point of water at 1 atm; Fahrenheit's zero is roughly the freezing point of a brine solution Daniel Gabriel Fahrenheit could reliably reproduce in 1724. All formulas on this site are exact within IEEE 754 double precision.