Gas Compressibility Factor Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 26, 2026Gas Compressibility Factor Calculator
Real gases only approximately follow the ideal gas law - the compressibility factor Z quantifies exactly how much a real gas deviates from ideal behavior under specific conditions.
The Formula
Z = PV / (nRT), using R = 8.314 kPa·L/(mol·K)
Worked Example
1 mole of gas occupying 22.4 L at standard conditions (101.325 kPa, 273.15K - the classic "molar volume at STP"): Z = (101.325 × 22.4) / (1 × 8.314 × 273.15) ≈ 0.999, confirming the gas behaves almost perfectly ideally at these familiar textbook conditions.
How to Use This Calculator
- Enter pressure, volume, moles, and temperature for your actual gas sample.
Z values noticeably below or above 1.0 signal real-gas effects becoming significant, typically at high pressure or near a gas's condensation point.