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Thermodynamics Calculators

Carnot Efficiency Calculator

Maximum possible efficiency of a heat engine between two temperatures, and COP for heat pumps.

Enter values

Results update as you type.

Result

Carnot efficiency

40%

Work per 1000 J of heat
400 J
COP (heat pump)
2.5
COP (refrigerator)
1.5

About the Carnot Efficiency Calculator

Maximum possible efficiency of a heat engine between two temperatures, and COP for heat pumps.

Also known as: carnot cycle, maximum heat engine efficiency, thermal efficiency limit.

How to use this calculator

  1. Enter hot reservoir temperature, cold reservoir temperature.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

η = 1 − T_cold / T_hot (temperatures in kelvin)

Worked example

Using the values pre-filled in the calculator above:

  • Hot reservoir temperature = 500 K
  • Cold reservoir temperature = 300 K

the calculator returns:

  • Carnot efficiency: 40%
  • Work per 1000 J of heat: 400 J
  • COP (heat pump): 2.5
  • COP (refrigerator): 1.5