Ideal Gas Volume CalculatorFree online other calculator — instant results, no sign-up
Calculate ideal gas volume from amount, absolute temperature and pressure.
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About the Ideal Gas Volume Calculator
The Ideal Gas Volume Calculator calculates a gas's volume in liters from its amount in moles, absolute temperature in kelvin, and absolute pressure in kilopascals. It applies the ideal gas law, V = nRT/P, using a gas constant matched to these units. With the default inputs of 1 mol, 298.15 K, and 101.325 kPa, the calculated volume is 24.465404 L.
- Amount (mol)
- The amount of gas is the quantity of substance in moles (mol), with a default of 1 mol.
- Absolute temperature (K)
- The absolute temperature is the gas temperature measured from absolute zero in kelvin (K), with a default of 298.15 K.
- Absolute pressure (kPa)
- The absolute pressure is the gas pressure measured relative to a vacuum in kilopascals (kPa), with a default of 101.325 kPa.
Formula and method
V = nRT/P; V = (1 mol × 8.314462618 L·kPa/(mol·K) × 298.15 K) / (101.325 kPa) = 24.465404 L, rounded to six decimal places.
- VCalculated ideal gas volume in liters (L).
- nAmount of gas in moles (mol).
- RUniversal gas constant, approximately 8.314462618 L·kPa/(mol·K).
- TAbsolute gas temperature in kelvin (K).
- PAbsolute gas pressure in kilopascals (kPa).
Multiply the amount of gas by the gas constant and absolute temperature, then divide by absolute pressure. The chosen units cancel to give liters without an additional volume conversion. For the default inputs, calculate (1 × 8.314462618 × 298.15) / 101.325 and round the result to six decimal places to obtain 24.465404 L.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Amount1 mol
- Absolute temperature298.15 K
- Absolute pressure101.325 kPa
Results
- Result24.465404 L
How to use the Ideal Gas Volume Calculator
- 1Enter the amount of gas in moles; use 1 mol to reproduce the default example.
- 2Enter the absolute temperature in kelvin; use 298.15 K for the default example.
- 3Enter the absolute pressure in kilopascals; use 101.325 kPa for the default example.
- 4Check that temperature and pressure are positive and that pressure is absolute rather than gauge pressure.
- 5Calculate and read the volume in liters; the default inputs give 24.465404 L.
Reading your result
The Result row reports the predicted ideal gas volume in liters at the entered temperature and pressure. For 1 mol at 298.15 K and 101.325 kPa, Result = 24.465404 L. This is the volume at those specific conditions, not a volume automatically converted to standard conditions. The displayed decimal places reflect numerical rounding, not guaranteed measurement accuracy.
Limitations
The calculation assumes ideal gas behavior: particles have negligible volume and intermolecular forces are ignored. Real gases can depart substantially from this model at high pressures, near condensation, or in other conditions where interactions matter. Use positive absolute temperature and pressure and a nonnegative amount of gas; zero pressure makes the formula undefined. Celsius temperatures and gauge pressures must be converted before entry. Accuracy also depends on the input measurements, and this model does not account for phase changes or chemical reactions that alter the amount of gas.
Common questions
Can I enter Celsius instead of kelvin?+
No. Convert Celsius to kelvin using T(K) = T(°C) + 273.15 before entering the temperature. The default 298.15 K corresponds to 25 °C.
Should I enter gauge pressure or absolute pressure?+
Enter absolute pressure. If you have gauge pressure, add the local atmospheric pressure using P_absolute = P_gauge + P_atmospheric, with both pressures expressed in kPa.
Why does the default calculation give 24.465404 L rather than about 22.4 L?+
The often-quoted molar volume of about 22.4 L applies at 273.15 K and 101.325 kPa. This calculator's default temperature is 298.15 K, so 1 mol occupies a larger ideal volume at the same pressure.
Why does the calculator not ask which gas I am using?+
The ideal gas law predicts the same volume for any gas with the same amount in moles, temperature, and pressure. Gas identity matters when converting mass to moles or correcting for real-gas behavior, neither of which is included here.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.