Heat Capacity Calculator (Q = mcΔT)
Solve Q = mcΔT for specific heat capacity, heat energy, mass or temperature change, and compare your result with common materials.
Specific heat capacity tells you how much energy it takes to warm one kilogram of a material by one kelvin. Water needs about 4,184 J for that, aluminium about 900 J and copper under 400 J. This calculator rearranges Q = mcΔT so you can find whichever of the four quantities you are missing, and it shows how the same job would look for a dozen common materials.
How to use this tool
- Choose what to solve for: specific heat capacity, heat energy, mass or temperature change.
- Enter the heat energy and pick its unit (J, kJ, cal, kcal, Wh or BTU).
- Enter the mass and pick kg, g or lb.
- Enter the specific heat capacity in J/(kg·K) if you know it, and the start and end temperatures.
- Read the answer, the heat capacity of the whole sample (m × c), and the comparison table.
Formula
Q = m × c × ΔT c = Q / (m × ΔT) C = m × c
Q is heat energy in joules, m mass in kg, c specific heat capacity in J/(kg·K) and ΔT the temperature change (final − initial) in kelvin, which is the same size as a degree Celsius. C, the heat capacity of the object, is the energy per kelvin for the whole sample rather than per kilogram.
Example
A 2 kg metal block warms from 20 °C to 30 °C after absorbing 18,000 J. c = 18,000 ÷ (2 × 10) = 900 J/(kg·K), which is close to the aluminium reference (897 J/(kg·K)). The block's heat capacity is 18,000 ÷ 10 = 1,800 J/K. Heating 2 kg of water by the same 10 °C would take 83.68 kJ, more than four times as much.
Frequently asked questions
What is the difference between heat capacity and specific heat capacity?
Heat capacity (J/K) belongs to a whole object: a full kettle has more than a half-full one. Specific heat capacity (J/(kg·K)) is per kilogram, so it is a property of the material itself.
Why is water's specific heat so high?
Hydrogen bonds between water molecules absorb energy that would otherwise raise the temperature. That is why lakes and oceans warm and cool slowly and why water works well as a coolant.
Can I use Fahrenheit?
Yes. Choose °F and the calculator converts the temperature difference using 1 °F = 5/9 K. The specific heat itself is always entered and shown in J/(kg·K).
Does specific heat change with temperature?
Yes. It depends on temperature, pressure and phase. The table combines approximate textbook references, including ice at −10 °C; large-range calculations assume a constant value and cannot model melting or boiling.
Sources
Last updated: 2026-10-30