Solve PV = nRT for any variable. Also includes the combined gas law P₁V₁/T₁ = P₂V₂/T₂ for before/after comparisons.
PV = nRT
R = 8.314 J/(mol·K) = 0.08206 L·atm/(mol·K)
SOLVE FOR:
mol
P₁V₁/T₁ = P₂V₂/T₂
Enter 5 of 6 values — the missing one will be solved
State 1 (Initial)
State 2 (Final)
About Ideal Gas Law Calculator
Scientific calculations require precision and understanding of the underlying formulas. Ideal Gas Law Calculator provides both — letting you solve pv = nrt for any variable. also includes the combined gas law p₁v₁/t₁ = p₂v₂/t₂ for before/after comparisons with instant results and educational context. Perfect for homework, lab work, or quick engineering estimates.
How to Use
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Enter your known valuesFill in the input fields with the values you have. The tool will calculate the unknowns.
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Why Use Ideal Gas Law Calculator?
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Verified FormulasIdeal Gas Law Calculator implements standard scientific formulas from physics, chemistry, and mathematics textbooks. Results you can trust for homework, research, and engineering.
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Great for StudentsWhether you're in high school physics or graduate-level engineering, Ideal Gas Law Calculator helps you check your work and build intuition for the underlying concepts.
Frequently Asked Questions
The ideal gas law PV = nRT relates the pressure (P), volume (V), amount (n in moles), and temperature (T in Kelvin) of an ideal gas. R = 8.314 J/(mol·K) is the universal gas constant. The law assumes gas molecules have no volume and no intermolecular forces — a good approximation at low pressures and high temperatures.
The ideal gas law becomes inaccurate at high pressures (when molecules are close together and intermolecular forces matter) and low temperatures (near the liquefaction point). Real gases are better modeled by the van der Waals equation: (P + a/V²)(V - b) = nRT, where a accounts for attractions and b for molecular volume.
STP is defined as 0°C (273.15 K) and 1 atm (101,325 Pa). At STP, one mole of an ideal gas occupies exactly 22.414 liters. IUPAC also defines SATP (Standard Ambient Temperature and Pressure) as 25°C and 1 bar, where one mole occupies 24.789 liters. STP is commonly used in stoichiometry calculations.