Kelvin is a unit of measurement to calculate temperature based on absolute scale. i.e the lowest minimum scale assigned is zero. When calculated in the Celsius temperature scale, the corresponding temperature will be 273.15° Celsius.  Thus, the boiling point of water is 100°C, the corresponding Kelvin temperature scale will be 373.15 K.
It is one of the base units recognized by International System of Units (SI) and its unit symbol is K. The temperature scale is named after the British mathematician and physicist William Thomson Kelvin, who proposed it in 1848.