Temperature can be given in degrees Kelvin (K), Celsius (C), Fahrenheit (F) or

Rankine (R). Both the Kelvin an Celsius scales have the same size degree but the

definition of their zero-points is different. For Celsius the zero-point is the temperature

of melting ice, for Kelvin it is the lowest temperature that theoretically can exist

within the universe, absolute zero. The difference in temperature between these two

reference values is 273 degrees Celsius so 0 degrees Kelvin corresponds with minus

273 degrees Celsius while 1000 degrees Celsius corresponds with 1273 degrees

Kelvin. 100 degrees Celsius is defined as the temperature of boiling water.

The zero-point of the Fahrenheit scale is not clearly defined but

it is somewhere around the freezing point of a solution of equal

parts of water and salt, about minus17 degrees Celsius.

Rankine has the same scale size as Fahrenheit but, as with

Kelvin, its zero point is absolute zero, minus 460 degrees

Fahrenheit.

96 degrees Fahrenheit is an early (somewhat too low)

estimation of the temperature of the human body, about 36

degrees Celsius, so 96 scale units Fahrenheit roughly

corresponds with 36 + 17 = 53 scale units Celsius and the

defined conversion factor is 9 to 5. Since 32 degrees

Fahrenheit corresponds with 0 degrees Celsius, a temperature

F in Fahrenheit can be converted to a temperature C in Celsius

with the formula C = (F - 32) * (5/9).

Fahrenheit and Rankine are used in the United States, its

territories and some associated states. Celsius and Kelvin are

used in the rest of the world.