Ideal Gas Law Calculator

The ideal gas law ties together pressure, volume, amount and temperature. Enter any three to find the fourth, in the units you have.

Results update as you type.

Volume

22.41397 L

In mL
22,413.97 mL
In m³
0.02241397 m³
In cm³
22,413.97 cm³

Real gases follow this closely at ordinary temperatures and pressures; it breaks down at high pressure or near condensation.

About this calculator

Temperatures in °C or °F are converted to kelvin automatically.

How to use it

  1. Choose what to find, enter the other values with their units, and read the answer in every common unit.

The formula

PV = nRT, R = 8.314 J/(mol·K) = 0.08206 L·atm/(mol·K)
P
pressure
V
volume
n
moles
T
absolute temperature

Worked example

1 mol at 1 atm and 0 °C

  1. T = 273.15 K.
  2. V = 1 × 0.08206 × 273.15 ÷ 1 = 22.41 L.

What the result means

Real gases behave nearly ideally at room temperature and normal pressure.

Assumptions

  • Ideal gas.

Limitations

  • Inaccurate at high pressure or low temperature.

Frequently asked questions

What is R?

The gas constant: 8.314 J/(mol·K), or 0.0821 L·atm/(mol·K).

Why must temperature be in kelvin?

The law is proportional to absolute temperature.

What is STP?

0 °C and 1 bar (older books: 1 atm).

Last reviewed on 6 October 2026. Found a mistake? Tell us.