Specific Heat Calculator

Choose a material, a mass and the temperatures to find the heat energy needed.

This result is an estimate only. Double-check important figures before relying on them.

How it is calculated

Q = mass × specific heat × (final − starting temperature)
Values used (J per kg per °C): water 4,186, aluminium 897, copper 385, iron 449, air 1,005
1 kWh = 3,600,000 J

To see what that costs, use the electricity bill calculator.

Worked example

Heating 1 kg of water from 20 °C to 100 °C:

Q = 1 × 4,186 × 80 = 334,880 J
That is 334.88 kJ, about 0.093 kWh

Why your number may differ

Specific heat changes slightly with temperature and with the exact alloy. Heat lost to the surroundings, and the energy needed to boil, are not included.

Frequently asked questions

What is specific heat?

The energy needed to raise 1 kg of a material by 1 °C. Water needs about 4,186 J, which is high compared with metals.

What is the formula?

Q = m × c × ΔT, where m is the mass, c the specific heat and ΔT the temperature change.

What does a negative answer mean?

The material is cooling, so that much heat is released.