Solve PV = nRT for the missing variable
Three knowns, one unknown — pressure, volume, moles or temperature, with unit conversion built in.
Tools used in this guide
The job
The ideal gas law links pressure, volume, amount and temperature. The classic lab task: fill three, solve the fourth — without juggling units by hand.
Leave the unknown empty
Enter any three of P, V, n, T in their units (kPa, L, mol, °C — pick what your data is in). The empty field is solved and shown with the value converted to SI.
- Worked example: 1 mol at 0 °C and 1 atm gives ≈ 22.4 L — the molar volume you expect.
- Temperature must be above absolute zero; the tool rejects 0 K and below.
Where the model ends
Real gases deviate at high pressure or near condensation — the ideal approximation is good for everyday lab ranges, not for liquification work or precision engineering.