Heat Transfer Calculator

The governing equation is:

$$Q = m \cdot c \cdot \Delta T$$

where Q is the heat energy transferred (J), m is the mass (kg), c is the specific heat capacity (J/(kg·K)), and ΔT = T_final − T_initial (K or °C, since the interval is the same).

A positive Q means the substance absorbs heat (endothermic process); a negative Q means it releases heat (exothermic). The equation assumes no phase change occurs during the process—if the substance melts or boils, the latent heat equation must be used instead.

Rearranging for any unknown:

$$m = \frac{Q}{c \cdot \Delta T}, \quad c = \frac{Q}{m \cdot \Delta T}, \quad \Delta T = \frac{Q}{m \cdot c}$$

Common specific heat values include water at 4186 J/(kg·K), aluminum at 897 J/(kg·K), iron at 449 J/(kg·K), and copper at 385 J/(kg·K). Water's exceptionally high specific heat explains why oceans moderate coastal climates and why water is used as a coolant in engines and power plants.

The calculated heat Q tells you the total thermal energy transferred. Large Q values at moderate ΔT indicate either a large mass or a material with high specific heat. If you are designing a heating system, Q directly determines the energy (and therefore fuel or electricity) required. For cooling applications, Q represents the energy that must be removed by a refrigeration or ventilation system.

When Q is negative, the object is losing heat to its surroundings. Conservation of energy dictates that the heat lost by one body equals the heat gained by another in an isolated system, the principle behind calorimetry experiments.