Carnot Heat Engine Calculator
Calculate the reversible maximum heat-engine efficiency, ideal work and rejected heat between two entered reservoir temperatures.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Convert both temperatures independently to kelvins. Apply the reversible Carnot efficiency, then use the cycle energy balance to split absorbed heat into ideal work and rejected heat.
ηmax=1−Tc/Th; Wmax=ηmax Qh; Qc=Qh−Wmax
Worked example
With Th=500 K, Tc=300 K and Qh=1000 J, maximum efficiency is 40%, ideal work is 400 J and rejected heat is 600 J.
Assumptions and input details
Reservoir temperatures must be absolute and Th>Tc. This is the reversible Carnot upper bound, not an efficiency prediction for a real engine. Power, cycle rate, working fluid, finite temperature differences, friction and other irreversibilities are excluded.
References: NASA Glenn: Carnot cycle · OpenStax: Carnot cycle
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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