Chemistry
The ideal gas law
The full equation of state. Pressure times volume on one side, amount times gas constant times absolute temperature on the other.
The Formula
P V = n R T
The full equation of state. Pressure times volume on one side, amount times gas constant times absolute temperature on the other.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| P | Pressure of the gas | pressure | Any pressure unit, provided the value of R matches it. |
| V | Volume occupied by the gas | volume | Usually litres or cubic metres, matching R. |
| T | Absolute temperature | kelvin | Kelvin only. Add 273.15 to a Celsius reading first. |
What Each Symbol Means
Ppressure
Pressure of the gas
Any pressure unit, provided the value of R matches it.
Vvolume
Volume occupied by the gas
Usually litres or cubic metres, matching R.
Tkelvin
Absolute temperature
Kelvin only. Add 273.15 to a Celsius reading first.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate the ideal gas law page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate The Ideal Gas Law, filed under Science. Every number the guide produces comes from substituting into this one line.