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Gas Law Calculator
Gas Law Calculator requires absolute temperature and says where the ideal model stops describing reality. Runs entirely in your browser with no upload and no.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Math & Science
Gas Law Calculator
Frontend preview — no upload or external service.
Result
At STP, 1 mole of gas occupies 22.4 L. Your inputs: 101325 Pa, 0.0224 m³, 273.15 K, 1 mol.
How the Gas Law Calculator works
- Enter the three known quantities and choose the fourth to solve for.
- Use absolute temperature. Kelvin is required; using Celsius produces answers that are wrong by a large and non-obvious factor.
- Check the note on real gas behaviour if you are working at high pressure or near condensation, where the ideal model breaks down.
The method
The ideal gas law relates pressure, volume, temperature and quantity through a single constant.
PV = nRT, with R = 8.314 J/(mol K)
Real gases deviate at high pressure and low temperature, where molecular volume and intermolecular forces stop being negligible.
FAQ
Why must temperature be in Kelvin?
Because the law is proportional to absolute temperature. Using Celsius, where zero is arbitrary, breaks the proportionality — doubling from 10 to 20 degrees Celsius is not doubling the absolute temperature.
When does the ideal gas law fail?
At high pressure and low temperature, where molecules occupy a meaningful fraction of the volume and attract each other. Near condensation the errors become large, and equations like van der Waals are used instead.
What is standard molar volume?
About 22.4 litres per mole at 0 degrees Celsius and 1 atmosphere. It is a useful check — any answer far from it for one mole near those conditions is probably a unit error.
How we compare
| Feature | Online Tool Store | A graphing calculator | A stats package |
|---|---|---|---|
| Solves for any variable | ✓ | ✓ | ✓ |
| Unit handling | ✓ | ✗ | ✓ |
| Real gas caveat | ✓ | ✗ | ✗ |
| No sign-up | ✓ | ✓ | ✗ |
Gas Law Calculator requires absolute temperature and says where the ideal model stops describing reality.