Gas Law Calculator
Combined Gas Law: P1V1/T1 = P2V2/T2. Solve for any unknown variable given the other five.
State 1 (Initial)
State 2 (Final)
P2
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atm
V2
--
L
T2
--
K
How this was calculated
Combined Gas Law: P1V1/T1 = P2V2/T2
Special cases: Boyle's Law (T constant): P1V1 = P2V2. Charles's Law (P constant): V1/T1 = V2/T2. Gay-Lussac's Law (V constant): P1/T1 = P2/T2.
Temperature must be in absolute units (Kelvin or Rankine).
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Book a free strategy call →Understanding the Combined Gas Law
The combined gas law relates pressure, volume, and temperature for a fixed amount of gas. It merges Boyle's Law (P inversely proportional to V at constant T) and Charles's Law (V proportional to T at constant P).
In petroleum engineering, this law is used for surface-to-downhole gas volume conversions, compressor calculations, gas metering corrections, and understanding gas behavior in wellbores.
For real gases at high pressure, apply the gas deviation factor (Z-factor): P1V1/(Z1T1) = P2V2/(Z2T2).
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