Ideal Gas Law and Boyle's Law Calculator
Solve PV = nRT and Boyle's law (P₁V₁ = P₂V₂) for any unknown. One shared unit per pair, worked steps, absolute pressure, and ideal-gas warnings.
Ideal gas result
Enter three values
PV = nRT uses absolute pressure and kelvin.
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Boyle's law: squeeze a gas and the pressure climbs
Seal a fixed amount of gas, hold the temperature steady, and volume and absolute pressure trade on a strict budget. Halve the volume and the pressure doubles. That budget is Boyle's law:
P₁V₁ = P₂V₂
Both pressures share one unit and both volumes share one unit, so the ratio cancels units and the answer comes back in whatever you typed. Because temperature and amount stay fixed, neither appears in the equation and there is no kelvin step.
Worked example. Compress 15.0 mL of gas at 13.0 psi down to 7.5 mL at the same temperature. Rearrange for the final pressure: P₂ = P₁V₁ / V₂ = 13.0 × 15.0 / 7.5 = 26.0 psi. Halving the volume doubled the pressure.
P * V = n * R * T
How?
How this is calculated
In PV = nRT mode the calculation converts pressure to kPa, volume to liters, amount to moles, and temperature to kelvin. It then rearranges the ideal gas law with R = 8.314462618 kPa L mol^-1 K^-1.
In Boyle's law mode both pressures share one unit and both volumes share one unit, so P₁V₁ = P₂V₂ runs in your native units with no conversion. There is no temperature or amount term.
The result assumes ideal-gas behavior. High pressure and low temperature can move real gases away from this approximation.
Formula: P * V = n * R * T
Sources
- NIST CODATA Fundamental Physical Constants. NIST. Retrieved .
- OpenStax Chemistry 2e, The Ideal Gas Law. OpenStax. Retrieved .
Method last reviewed