Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Fugacity (atm)

Required number input.

Pressure (atm)

Required number input.

Compute fugacity coefficient phi = f/P. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Phi coefficient

The resulting phi coefficient returned as a number.

• Simple gas relationships often assume equilibrium and ideal-gas behavior. High pressure, low temperature, condensation, composition changes, and nonzero compressibility can require a real-gas equation of state.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Fugacity Calculator

  Compute fugacity f = phi * P.

• Fugacity From Z

  Estimate gas fugacity from a pressure-virial compressibility factor using ln(phi) ≈ Z-1 and f = phi·P; this second-virial approximation is for low pressure.

• Osmotic Coefficient Calculator

  Compute osmotic coefficient phi = osmolality/(i*m).