Kelvin to Celsius
Absolute to everyday Celsius
Subtract 273.15 from a kelvin reading to get °C. Useful when journals quote activation energies alongside T in K but your thermostat thinks in °C. Remember: negative Celsius values are common; kelvin values are never negative in classical thermodynamics.
When to use it
Superconductivity thresholds, PCR protocol tweaks expressed in K in papers, or GPU junction specs. For Fahrenheit intuition after converting, use Celsius to Fahrenheit.