Thermochemical Calorie to Joule Converter

About this calculator

The word “calorie” is actually ambiguous — the thermochemical calorie (cal_th) is one of several historical definitions of the unit, fixed by exact convention at 1 cal_th = 4.184 joules, distinct from the slightly different “15°C calorie” and the International Table calorie once used in engineering. It originated as the energy needed to raise one gram of water by one degree Celsius, but is now defined directly in terms of the joule, the SI unit of energy, rather than measured experimentally.

This converter switches between thermochemical calories and joules in either direction using that exact 4.184 factor. It's relevant in chemistry and thermodynamics, where reaction energies are still often reported or found in older references in calories, and unit consistency matters when combining that data with SI-based calculations that use joules throughout.