Absolute temperature

absolute measure of temperature

Absolute temperature, also called thermodynamic temperature, is the temperature of an object on a scale where 0 is taken as absolute zero. Absolute temperature scales are Kelvin and Rankine.

Absolute zero is the temperature at which a system is in the state of lowest possible (minimum) energy. As molecules approach this temperature their movements drop towards zero. It is the lowest temperature a gas thermometer can measure. No electronic devices work at this temperature. No living thing can live in this temperature. The Kinetic energy of the molecules becomes negligible or zero.


Common temperatures in the absolute scale are:

  • 0 °C (freezing point of water) = 273.15 K
  • 25 °C (room temperature) = 298.15 K
  • 100 °C (boiling point of water) = 373.15 K
  • 0K (absolute zero) = - 273.15 Celsius
  • 233.15K (equal measures in Celsius and Fahrenheit)=-40 Celsius
  • Triple point of water= 273.16K (equal measure in Celsius) 0.01°c.


To convert from the Celsius scale into the absolute temperature, you add 273.15 and change °C to K. To get a temperature on the absolute scale to the Celsius scale, subtract 273.15 and change K to °C. This is normally used in the science world. Kelvin is used globally as a part of the International System of Units. It is one of the 7 base units of the system. The value of Absolute temperature is 0K.

  • Celsius to Kelvin: K=C+273.15
  • Kelvin to Celsius: C=K-273.15
  • Fahrenheit to Rankine: R=F+459.67
  • Rankine to Fahrenheit: F=R-459.67