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Ideal Gas Law Calculator

PV = nRT. Enter any three known values and instantly solve for the fourth.

Pressure

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atm

Volume

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L

Moles

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mol

Temperature

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K

Pressure

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psi

Temperature

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°C

Temperature

--

°F

How this was calculated

PV = nRT where R = 0.082057 L·atm/(mol·K)

P = nRT/V, V = nRT/P, n = PV/(RT), T = PV/(nR)

Conversions: 1 atm = 14.696 psi, K = °C + 273.15, °F = °C × 9/5 + 32

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Understanding the Ideal Gas Law

The ideal gas law PV = nRT combines Boyle's Law, Charles's Law, and Avogadro's Law into one equation. It describes the behavior of an ideal gas where molecules have negligible volume and no intermolecular forces.

In petroleum engineering, the ideal gas law provides a starting point for gas volume calculations, surface/downhole conversions, and gas-in-place estimates. Real gas behavior is captured by the gas deviation factor (Z-factor): PV = ZnRT.

At standard conditions (14.696 psia, 60°F / 520°R), one mole of ideal gas occupies about 379.4 scf.

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Disclaimer: For estimation only. Real gases deviate from ideal behavior at high pressure and low temperature.