Ideal Gas Law Calculator
Solve the ideal gas law for pressure, volume, temperature or amount of substance.
The defaults are standard conditions
One mole of an ideal gas at 101,325 Pa occupying 22.4 litres comes out at 273.15 K — exactly 0 °C. That is the definition of standard temperature and pressure, and it is a useful sanity check every time you use this equation.
When real gases stop behaving
The ideal gas law assumes molecules have no volume and do not attract each other. It is accurate within about 1% for most gases at everyday pressures, and it fails badly near condensation — at high pressure or low temperature you need the van der Waals equation instead.
What this page needs from you
This page asks for pressure in Pa, volume in m³, amount of gas in mol and solve for. From those it returns temperature in K. Every figure updates as you type, and nothing you enter leaves your browser.
Where lab results and calculated results part company
These relations describe ideal behaviour: ideal gases, complete reactions, fully dissociated strong acids, no side products. Real yields fall short, real gases deviate near condensation, and real solutions show activity effects at higher concentrations. The calculated figure is the target to compare a measurement against, not a prediction of what the flask will contain.
The formula
PV = nRT, with R = 8.314462 J/(mol·K)
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Ideal Gas Law Calculator
- Fill in each field with your own figures — the defaults are only there as an example.
- The result updates as you type, so there is no button to press.
- Check the breakdown under the main result for the supporting numbers.
- Use the copy button to take the result with you, or share the link to reload the same inputs.
Ideal Gas Law Calculator — frequently asked questions
Is this ideal gas law calculator free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
How accurate is the result?
The maths is exact for the formula shown on the page. Accuracy in the real world depends on your inputs and on assumptions the formula cannot see, so treat the output as a well-grounded estimate rather than a quote.
Can I use it on my phone?
Yes. The page is responsive, weighs a few kilobytes and works offline once loaded, so it behaves the same on a phone as on a desktop.
What people search for
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About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed September 14, 2026 · Calculation runs client-side · No data collected · Report an error