On the absolute scale, temperature is expressed in Kelvin.
A temperature scale, zero of which is equivalent to -273.15 °C and 373.15 °C is equivalent to 100 °C, is called absolute scale of temperature and -273.15 °C is called absolute zero. Absolute temperature is used in application of the ideal gas law and many other laws of thermodynamics.
What are temperature scales?
Temperature is a measure of the amount of heat energy possessed by an object. There are three main scales commonly used in the world today to measure temperature: the Fahrenheit (°F) scale, the Celsius (°C) scale, and the Kelvin (K) scale. Each of these scales uses a different set of divisions based on different reference points.