Specific Heat Calculator
Solve Q = mcΔT for heat, mass, specific heat, or temperature change.
Water: c = 4.184 J/(g·°C). ΔT is final − initial.
The heat to change a substance’s temperature is Q = m × c × ΔT — mass times specific heat times temperature change. Warming 100 g of water (c = 4.184 J/g·°C) by 10 °C takes Q = 100 × 4.184 × 10 = 4184 J (about 4.18 kJ).
Heating and cooling
The heat needed to change a substance’s temperature is Q = mcΔT — mass times specific heat times the temperature change. The specific heat (c) is the energy needed to warm one gram by one degree, so a high c means the substance stubbornly resists changing temperature.
Q = heat (J), m = mass (g), c = specific heat (J/g·°C), ΔT = temperature change (°C)
Worked example
How much heat warms 100 g of water (c = 4.184 J/g·°C) by 10 °C?
- 1 Write the specific heat equation. Q = m × c × ΔT.
- 2 Substitute the values. Q = 100 g × 4.184 J/g·°C × 10 °C.
- 3 Compute the heat. Q = 4184 J — about 4.18 kJ to raise that water by 10 degrees.
Specific heats of common substances
At roughly room temperature. Water’s value is unusually high.
| Substance | c (J/g·°C) | Note |
|---|---|---|
| Water (liquid) | 4.184 | Reference value |
| Ethanol | 2.44 | Common solvent |
| Ice | 2.09 | Solid water |
| Aluminium | 0.897 | Light metal |
| Iron | 0.449 | Heats quickly |
| Copper | 0.385 | Good conductor |
| Gold | 0.129 | Very low c |
Signs, scope, and common mistakes
The sign of Q tells the direction. A positive Q means heat is absorbed and the temperature rises; a negative Q means heat is released and the temperature falls. ΔT is always final temperature minus initial.
This does not cover phase changes. Melting or boiling happens at constant temperature and uses latent heat (Q = mL) instead. Q = mcΔT only applies while the substance stays in one phase.
Common mistake: mixing mass units with the specific heat. This tool uses J, grams, J/(g·°C), and °C — if your c is in J/(kg·°C), put mass in kilograms. A ΔT in °C equals the same ΔT in kelvin.