Polytropic Process Work Calculator

About this calculator

A polytropic process describes a gas that expands or compresses according to PV^n = constant, where n (the polytropic index) captures how much heat transfer occurs during the process — n=1 is isothermal, n equal to the specific heat ratio γ is adiabatic (no heat exchange), and everything in between represents partial heat transfer, which is what real compressors and expanders actually experience. The work done during such a process is W = (P1·V1 − P2·V2)/(n − 1), and this calculator evaluates it from the start and end pressures, volumes and the chosen index.

This formula is core material in engineering thermodynamics, used to size and analyze reciprocating and rotary compressors, gas turbines, and internal combustion engine cycles, where the polytropic index is often determined experimentally since real machines rarely behave exactly isothermally or adiabatically. Mechanical and chemical engineers use it during equipment selection to estimate the power a compressor motor must deliver, and it's a standard problem type in thermodynamics coursework for exactly that reason.