Heat Transfer Calculator — Q = mcΔT
Calculate the heat absorbed or released by any substance when its temperature changes. Select the material to use its standard specific heat capacity — or enter your own — then supply the mass and temperatures to get the result in kJ, J, kWh and calories.
Material
kg
°C
°C
Energy the substance absorbs as it warms up
Write the sensible-heat formula
Substitute values
Result
- 1
Temperature change
ΔT = 100 − 20 = 80 °CA positive ΔT means heat is absorbed; negative means it is released. - 2
Heat energy Q = m × c × ΔT
Q = 1 × 4,186 × 80 = 334,880 J - 3
Convert to kilojoules
Q_kJ = 334,880 ÷ 1000 = 334.88
How does this calculator work?
Heat transferred Q = m × c × ΔT (joules), where m is mass (kg), c is specific heat capacity (J/kg·K), and ΔT is the temperature change (K). Water c = 4 186, aluminium c = 897, steel c = 490, copper c = 385 J/kg·K. A positive Q means heat absorbed; negative means heat released.
Formula
How this is calculated
When the temperature of a substance changes without a phase transition, the heat exchanged is called sensible heat. The formula Q = m × c × ΔT (joules) links three quantities: mass m (kg), the specific heat capacity c (J/kg·K), and the temperature change ΔT = T_final − T_initial (K, or equivalently °C). A positive Q means heat flows into the substance (it warms up); a negative Q means it releases heat (it cools down).
Specific heat capacity is a material property — it is the energy needed to raise 1 kg of a substance by 1 K. Water has one of the highest values at 4 186 J/kg·K, which is why it is widely used as a heat transfer medium in central-heating systems and for thermal storage. Metals like copper (385 J/kg·K) and steel (490 J/kg·K) have much lower values, meaning they heat up quickly but also lose heat fast. Values given here are at approximately 25 °C; they vary slightly with temperature.
This calculator covers only sensible heat — it does not account for latent heat during phase changes (melting, boiling). If the temperature crosses 0 °C for ice/water or 100 °C for water/steam, the actual energy required is larger because the latent heat of fusion (334 kJ/kg) or vaporisation (2 257 kJ/kg) must also be added.
Frequently asked questions
Specific heat capacity (c) is the energy required to raise 1 kg of a substance by 1 K, in J/kg·K. Values for common substances appear in engineering data tables and physics textbooks. Notable values: water 4 186, aluminium 897, steel 490, copper 385 J/kg·K. This calculator provides standard values for the most common materials.
No — Q = mcΔT covers only the sensible heat (temperature change without a phase change). If the substance crosses a phase-change boundary (ice melting at 0 °C, water boiling at 100 °C), the latent heat must be calculated separately and added. For water: latent heat of fusion = 334 kJ/kg; latent heat of vaporisation = 2 257 kJ/kg.
For everyday masses and temperature changes, the joule produces large numbers (1 litre of water heated by 80 °C = 334 880 J). Kilojoules (kJ) and kilowatt-hours (kWh) are more practical for engineering and energy billing; the raw value in joules is also shown in the secondary stats. 1 kWh = 3 600 kJ.
Also known as
TG we-Calculate Editorial Team. (2026). Heat Transfer Calculator — Q = mcΔT [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/heat-transfer-calculator
TG we-Calculate Editorial Team. "Heat Transfer Calculator — Q = mcΔT." TG we-Calculate. 2026. https://we-calculate.com/calculator/heat-transfer-calculator.
TG we-Calculate Editorial Team, "Heat Transfer Calculator — Q = mcΔT," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/heat-transfer-calculator
@misc{wecalculate_heat_transfer_calculator, title = {Heat Transfer Calculator — Q = mcΔT}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/heat-transfer-calculator}}, year = {2026}, note = {TG we-Calculate} }
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