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Thermodynamics Calculators

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.

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.

Carnot Efficiency 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