Specific Heat Calculator
Calculate heat energy with Q = mcΔT, or find mass, temperature change or specific heat, plus heating time.
About the Specific Heat Calculator
Specific heat capacity is the energy needed to warm 1 kg of a material by 1 °C. Water's is unusually high, 4,184 J/kg·K, which is why seas warm slowly and a kettle takes minutes. Heating 1.5 L of water from 20 °C to 100 °C needs about 502 kJ; a 2 kW kettle delivering 90% of its power into the water takes about 4.6 minutes. This ignores phase changes: melting or boiling need extra latent heat.
The formula
Q = m × c × ΔT; time = Q ÷ (power × efficiency)
Specific heat capacities near room temperature
| Material | J/kg·K |
|---|---|
| Water (liquid) | 4,184 |
| Ice | 2,108 |
| Steam | 2,010 |
| Aluminium | 897 |
| Copper | 385 |
| Iron | 449 |
| Steel (carbon) | 490 |
| Glass | 840 |
| Air (constant pressure) | 1,005 |
| Concrete | 880 |
| Olive oil | 1,970 |
| Ethanol | 2,440 |
| Gold | 129 |
| Silver | 235 |
| Lead | 129 |
Worked example
Example: Heat energy = 625.9264 kJ
- Inputs: Find: Heat energy Q; Material: Water (liquid) (4184 J/kg·K); Mass: 1.7 kg; Temperature change: 88 °C or K; Heater power (optional): 2,200 W; Heater efficiency: 99%.
- Formula: Q = m × c × ΔT; time = Q ÷ (power × efficiency)
- Result: Heat energy = 625.9264 kJ
Questions people ask
Does boiling need more energy?
Yes: turning water at 100 °C into steam needs 2,257 kJ per kg on top.
Is a change of 1 °C the same as 1 K?
Yes, for temperature differences.