The equation
Formula and assumptions
PV = nRT
Inputs use Pa, m³, mol, and K with R = 8.314462618 J·mol⁻¹·K⁻¹.
Worked examples
See the method in practice
01
Room-temperature gas
One mole at 100 kPa and 298.15 K occupies about 0.02479 m³, or 24.79 L.
02
Solving temperature
Rearrange to T = PV/nR when pressure, volume, and amount are known.
Questions
Frequently asked
Why must temperature be in kelvin?
The gas law requires an absolute temperature scale; Celsius cannot be inserted directly.
When does the ideal gas law become inaccurate?
Real gases deviate most at high pressure, low temperature, and near phase changes.
Sources & review
Equations and examples are checked against the references below. Results are educational and should be independently verified for safety-critical work.
OpenStax Chemistry — the ideal gas lawWritten by the STEM Hub editorial team · Reviewed August 11, 2026 · Review methodology