Thermal Energy Calculator

Calculate the thermal energy required to change a substance temperature using mass, specific heat capacity, and temperature change.

THERMAL ENERGY
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In kJ
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In kcal
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In BTU
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In kWh
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Table of Contents

  1. What Is Thermal Energy?
  2. Heat Equation
  3. Specific Heat Table
  4. FAQ

What Is Thermal Energy?

Thermal energy is internal kinetic energy from random molecular motion. Adding heat raises temperature. The energy needed depends on mass, specific heat, and temperature change. Water has exceptionally high specific heat (4186 J/kgK), making it an excellent coolant and thermal storage medium. Metals have lower values, heating up faster.

This concept underlies HVAC design, cooking, industrial processes, and climate science. The heat equation Q=mcΔT is one of the most commonly used formulas in physics and engineering.

Heat Equation

Q = m × cp × ΔT

Specific Heat of Common Substances

Substancecp (J/kgK)
Water4186
Ice2090
Aluminum900
Iron450
Copper385
Air1005

FAQ

How much energy to heat bath water?

150L from 15 to 40°C: Q = 150 × 4186 × 25 = 15.7 MJ = 4.4 kWh, costing about $0.53 at $0.12/kWh.

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