The heat equation q = mcΔT links the energy q transferred to a substance with its mass m, specific heat capacity c, and temperature change ΔT. This calculator solves for whichever quantity you choose, shows the result in joules and kilojoules, and notes whether heat is absorbed or released.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: the calorimetry equation, recomputed in code.
The formula, rearranged
Specific heat capacity is the energy to raise 1 gram by 1 °C. Water's is unusually high (4.184 J/g·°C), so it stores a lot of heat and resists temperature swings; metals are far lower. A positive ΔT (warming) gives a positive q — heat absorbed; a negative ΔT (cooling) gives a negative q — heat released. The equation holds only within one phase, with no melting or boiling.
Worked examples
Heat 100 g of water by 25 °C:
Heat 50 g of copper by 30 °C:
Find c from q = 577.5 J, m = 50 g, ΔT = 30 °C:
Because water's specific heat is more than ten times copper's, the same 50 g warmed 30 °C would take about 6,276 J for water versus 578 J for copper — which is why a metal pan heats up so much faster than the water in it.
Frequently Asked Questions
q = mcΔT. Rearrange to solve for m, c or ΔT.
≈ 10,460 J (10.46 kJ), using c = 4.184.
Energy to raise 1 g by 1 °C. Water 4.184, copper 0.385 J/g·°C.
Heat is released (the substance cools, ΔT < 0).
No — phase changes use latent heat, q = mL, at constant temperature.