This scale sets the lowest obtainable temperature (absolute zero = the temperature at which all molecular motion completely ceases) to 0 degrees. A change of one degree Celsius = a change of one Kelvin, but a Celsius temperature is never equal to a Kelvin temperature. There are no negative temperatures in the Kelvin scale. To convert a Kelvin temperature to Celsius, subtract 273.15. Note: simply use "Kelvin" or "Kelvins", not "degrees Kelvin" when using this unit