Which equation converts Celsius to Kelvin?

The correct equation for converting Celsius to Kelvin is K = C + 273. This relationship is based on the fact that the Kelvin scale is an absolute temperature scale that starts at absolute zero, which is 0 K. The Celsius scale is defined such that 0 °C corresponds to 273.15 K. For practical purposes in many scientific contexts, the simpler conversion used is K = C + 273, where 273 is used as a rounded value to simplify calculations.

Kelvin temperatures are always positive, and the conversion reflects the shift in the starting point of the two scales. Therefore, to obtain the Kelvin temperature from Celsius, you need to add 273 to the Celsius temperature.