How this calculation works
A temperature difference of one degree Celsius is the same size as one kelvin. Positive heat raises temperature under the stated model; negative heat represents cooling. The default heat capacity is an example value.
Heat = mass × specific heat capacity × temperature changeA worked example
2 kg with a specific heat capacity of 4,184 J/(kg·K) changing by 10 K requires 83,680 J.
Good to know
Assumes constant heat capacity and no phase change, heat loss or other work.
A temperature difference is not an absolute temperature
A rise of 10°C has the same size as a rise of 10 K. That is why either can express the temperature change in this equation, even though an absolute reading of 10°C is not 10 K.
With mass and heat capacity fixed, doubling the temperature change doubles the modeled heat transfer. Likewise, heating twice the mass through the same change requires twice the energy under the assumptions.
A phase change needs another energy term
Melting or boiling can involve energy transfer without the temperature change predicted by this simple sensible-heat equation. Latent heat and the relevant phase conditions must be considered separately.
Use a heat capacity appropriate to the material and conditions. The tool assumes it is constant and excludes heat losses to the surroundings, container heating and mechanical work.
A few questions, answered
Why can the heat result be negative?
A negative temperature change represents cooling and a negative sensible-heat change under the chosen sign convention.
Can I calculate boiling energy with this alone?
No. Heating to a phase change and the phase change itself require separate treatment.