Volume of Gas Calculator
How Much Space Does a Gas Actually Take Up?
Unlike a solid or liquid, a gas doesn't have a fixed volume of its own — it expands to fill whatever container holds it, and how much room that takes depends entirely on how many moles are present, the temperature, and the pressure pushing back. This calculator isolates the volume term from the ideal gas law so you can answer that question directly from the other three variables.
The Formula
R = 0.0821 L·atm / (mol·K)
This is the same ideal gas law rearranged to solve for volume specifically. Temperature entered in Celsius is converted to kelvin internally before the calculation runs, since the gas constant above is defined in kelvin.
Where This Calculation Matters
- Balloon and airbag inflation — predicting the volume a known quantity of gas will occupy at a target pressure and temperature.
- Lab gas collection over water — estimating the expected volume of a gas product before running a reaction helps size the collection apparatus.
- HVAC and industrial gas handling — sizing pipework and vessels around expected gas volumes at operating temperature and pressure.
- Cross-checking experimental yield — comparing a measured gas volume against the theoretical volume from moles reacted flags errors early.
Volume of 1 Mole at Common Temperatures (1 atm)
| Condition | Volume (1 mol, 1 atm) |
|---|---|
| 0 °C (STP) | 22.426 L |
| 25 °C (room temperature) | 24.478 L |
| 37 °C (body temperature) | 25.463 L |
How to Use This Calculator
- Enter the Moles (mol) of gas present.
- Enter the Temperature and select whether it's in Celsius or kelvin.
- Enter the Pressure (atm).
- Select Calculate to get the volume in liters.
Related Calculations
Need to solve for pressure, moles, or temperature instead of volume? The full Gas Law Calculator solves the ideal gas law in any direction. Once you know moles, the Molarity Calculator can convert that into a solution concentration.