Work out heat energy (q = mcδt) instantly with clear inputs, formula shown and shareable results.
Q = mcdT is the workhorse of calorimetry: heating 5 kg of water by 40 K takes 837 kJ, which a 2 kW immersion heater delivers in about 419 seconds. The relation assumes no phase change - crossing a melting or boiling point needs latent heat added separately.
Sensible heat
Q = m x c x dT
Heating time
t = Q / power
Heat leaks to the surroundings and warms the kettle body itself, so real efficiency is typically 80-90%.
Then latent heat takes over at constant temperature - about 2260 kJ per kilogram, far more than raising it to boiling point.