Converting Celsius to Kelvin is straightforward: simply add 273.15 to the Celsius temperature. This means that 0°C is equivalent to 273.15K, as the Kelvin scale starts at absolute zero (0K), the point where molecular motion ceases. Both scales have the same interval magnitude, so a change of 1°C equals a change of 1K. This direct relationship makes conversions between Celsius and Kelvin simple and essential for scientific calculations.