Specific Heat Calculator
Calculate specific heat capacity from heat, mass and temperature change, in J/kg·K, cal/g·°C and BTU/lb·°F, and compare it with common materials.
Specific heat capacity is the energy needed to warm one kilogram of a substance by one degree. This calculator finds it from a measurement: the heat put in (or given off), the mass of the sample, and its starting and ending temperatures. It reports the answer in J/kg·K, kJ/kg·K, cal/g·°C and BTU/lb·°F, gives the heat capacity of the whole sample, and names the common material with the nearest value.
How to use this tool
- Enter the heat supplied or released and its unit — for an electric heater, power × time in seconds gives joules.
- Enter the mass of the sample.
- Pick the temperature scale and enter the starting and final temperatures.
- Read the specific heat and compare it with the table of common substances.
Formula
c = Q ÷ (m × ΔT)
The displayed estimate uses |Q| ÷ (m × |ΔT|), with a sign warning if heat and temperature changes disagree. It assumes one phase, negligible other work and heat transferred to the sample itself. Specific heat depends on material, state, temperature and constraint, not sample mass. The closest table entry uses relative difference on a logarithmic scale and cannot identify a material.
Example
A 0.5 kg aluminium block warms from 20 °C to 80 °C after absorbing 27 kJ. Then c = 27,000 ÷ (0.5 × 60) = 900 J/kg·K, or about 0.215 cal/g·°C, which matches the textbook value for aluminium. The block’s heat capacity is 450 J/K.
Frequently asked questions
What is the difference between specific heat and heat capacity?
Specific heat is per kilogram and belongs to the material. Heat capacity belongs to a particular object: a 2 kg pot has twice the heat capacity of a 1 kg pot made of the same metal.
Why is my measured value higher than the table?
Heat lost to the container, the thermometer and the room is the usual reason. If you count all the heater’s energy as going into the sample, losses make c look too high. Insulate the sample and stir liquids to reduce the error.
Constant pressure or constant volume?
For gases, constant-pressure and constant-volume heat capacities differ. The table gives reference dry-air values of about 1,015 and 721 J/kg·K respectively. A constant-pressure determination must account for the same sample mass and any mass flow; simply opening a container is not sufficient.
Sources
Last updated: 2026-10-30