Thermodynamic process & PV diagram calculator (ideal gas)

How to use (3 steps)

Enter the initial state (n, P₁, V₁, γ). Defaults show a 1 mol, 1 atm, room-temperature example.
Select the process type (isothermal, isobaric, isochoric, adiabatic, polytropic) and fill V₂ or T₂ as required.
Tap Compute to see W, ΔU, Q, the PV curve, and the calculation steps. Copy URL shares the exact setup.

Sign convention: work W is positive when the gas does work on the surroundings; Q is positive when heat flows into the gas.

Amount of gas n mol

Initial pressure P₁ kPa

Initial volume V₁ L

Heat capacity ratio γ = Cₚ / Cᵥ

Process type

Final volume V₂ L

Final temperature T₂ K

Polytropic exponent n

Number of points for PV curve

Initial and final states	Pressure	Volume	Temperature	Moles

Energy and work	J

What assumptions does this calculator make?

It assumes an ideal gas and quasi-static processes with constant γ. The state is always in equilibrium so the ideal gas law applies at each step.

How is the sign of work W defined here?

Work is positive when the gas does work on the surroundings (expansion gives W > 0). The first law is written as ΔU = Q − W.

Why might Q for an adiabatic process be non-zero?

Numerical rounding can leave tiny residuals even though the theoretical value is Q = 0. ΔU and W are consistent with ΔU = Q − W.

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