Heat Input Calculator

Calculate heat energy required to raise temperature. Enter mass, specific heat, and temperatures. Get Q in Joules, kJ, and kWh. Based on Q=mcΔT. Informational only—consult a physics textbook.

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Published: October 23, 2025 | Updated: October 23, 2025 | Reviewed by: Science/Physics Editor

Substance Properties

Preset Substances

Common Specific Heats

SubstanceSpecific Heat (J/kg·K)
Water4186
Aluminum900
Air1005
Iron450
Copper385

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How it works

Q = m × c × ΔT. We calculate the temperature change (ΔT) and multiply it by the mass and specific heat capacity to find the total heat input (Q).

The formula accounts for the mass of the substance, its ability to absorb heat (specific heat), and the desired temperature change.

Inputs explained

  • Mass: The amount of substance being heated (kg or lbs)
  • Specific Heat Capacity: Energy needed to raise 1 kg by 1°C (J/kg·K)
  • Initial Temperature: Starting temperature of the substance
  • Final Temperature: Desired ending temperature
  • Time: Optional duration for power calculation

Example

Heating water from 20°C to 100°C:

  • Mass (m) = 1 kg
  • Specific Heat (c) = 4186 J/kg·K
  • ΔT = 100 - 20 = 80°C

Calculation:

Q = 1 × 4186 × 80 = 334,880 J = 334.88 kJ

Tips & notes

  • Specific heat capacity is the amount of energy needed to raise the temperature of 1 kg of a substance by 1°C
  • Water has a very high specific heat capacity, which is why it's used for cooling
  • This calculation assumes no heat loss to the environment
  • The formula doesn't account for phase changes (melting, boiling)

FAQs

Q = m × c × ΔT, where m is mass, c is specific heat, and ΔT is the temperature change.

The amount of heat energy required to raise the temperature of a unit mass of a substance by one degree.

Calculate Q in Joules, then divide by 3,600,000 (the number of Joules in a kWh).

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Disclaimer

Informational tool based on the physics formula Q=mcΔT. Does not account for heat loss or phase changes. Consult a physics textbook for detailed theory.

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