Heat Calculator
Calculate heat energy absorbed or released by any substance using Q = m·c·ΔT.
How it works
- 1Enter the mass of the substance and choose metric (kg) or imperial (lb) units.
- 2Enter the specific heat capacity c in J/(kg·K) — water is 4186, aluminium 897, iron 449.
- 3The tool computes Q = m·c·ΔT and shows the result in joules, kilojoules, and kilocalories.
Use cases
- Heating and cooling load estimates for HVAC and building physics.
- Chemistry and lab work — energy changes during reactions or experiments.
- Engineering design — sizing heaters, coolers, and heat exchangers.
Frequently asked questions
What formula does this calculator use?
Q = m·c·ΔT, where Q is heat in joules, m is mass in kg, c is specific heat in J/(kg·K), and ΔT is the temperature change in kelvin (equal to a Celsius difference). It assumes no phase change occurs.
What is specific heat capacity, and why is water’s so high?
Specific heat is the energy to raise 1 kg of a substance by 1 K. Water’s ≈ 4186 J/(kg·K) is among the highest of common substances, thanks to hydrogen bonding — which is why water is a great coolant and coastal climates are mild.
Can you show a worked example?
Heating 2 kg of water by 10 °C: Q = 2 × 4186 × 10 = 83,720 J ≈ 83.7 kJ ≈ 20 kcal — about what a kettle uses to warm a mug of water.
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