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Ideal gas law calculator

Compute the pressure of a gas from moles, temperature and volume (PV = nRT).

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The Ideal gas law calculator turns Moles (n), Temperature (K), Volume (L) into Pressure (atm), instantly and for free. For instance, with Moles (n) = 1, Temperature (K) = 300 and Volume (L) = 24.5 it returns Pressure (atm) = 1.005.

How to use it

  1. Enter your values: Moles (n), Temperature (K), Volume (L).
  2. Read the result instantly: Pressure (atm).

Frequently asked questions

What does the Ideal gas law calculator actually compute?

It takes Moles (n), Temperature (K) and Volume (L) and derives Pressure (atm) from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

3 values: Moles (n), Temperature (K) and Volume (L). Nothing else is required — no account, no file upload.

Can you show a worked example?

With Moles (n) = 1, Temperature (K) = 300 and Volume (L) = 24.5, the calculator returns Pressure (atm) = 1.005. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

What happens if I enter larger values?

It moves a lot. Using Moles (n) = 2, Temperature (K) = 600 and Volume (L) = 27 instead, Pressure (atm) goes from 1.005 to 3.647 — which is why it is worth testing a few scenarios rather than trusting a single figure.

What does it give for smaller values?

Scaled down to Moles (n) = 0.5, Temperature (K) = 150 and Volume (L) = 22.1, Pressure (atm) comes out at 0.278. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Preparing a solution at a stated concentration, working out how much of a reagent a reaction needs, and converting between mass, moles and volume.

What is the most common mistake?

Confusing molarity with molality. One is per litre of solution and the other per kilogram of solvent; they diverge as concentration rises, and only one of them is temperature-independent.

What is the difference between the Ideal gas law calculator and the Beer-Lambert law calculator?

This one returns Pressure (atm); the Beer-Lambert law calculator returns Result and Unit of result. That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

Molarity calculator is the closest one after this: Compute the molar concentration of a solution from moles and volume.

What else is worth having open alongside it?

Coulomb's Law Calculator and Hooke's law calculator — they come up in the same task often enough to be worth a second tab.

Further reading

All guides →
ExplainerThe Ideal Gas Law Explained: PV = nRT, R in Every Unit, and Where It BreaksPV = nRT holds when the gas is dilute and far from condensing. The value of R depends entirely on the units you feed it, and the temperature is never in degrees Celsius.How-toHow to Calculate pH — And When the Weak-Acid Shortcut Stops WorkingFour routes for four kinds of solution, each worked with real numbers. Including the part most pages leave out: the square-root formula for a weak acid is an approximation with a validity limit, and it fails quietly.How-toHow to Calculate a Dilution with C1V1 = C2V2Solve for the missing term, then convert the answer into a bench instruction. The step almost everyone skips is that the solvent you add is V2 minus V1, not V2.ExplainerHooke's Law Explained: F = kx, Real Spring Constants, and Where It Stops HoldingHooke's law says force is proportional to stretch — but only below the elastic limit. Here is F = kx with worked numbers, what a 200 N/m spring actually feels like, and how springs combine.ExplainerHow Half-Life Works: What Is Left After 1, 3 and 10 Half-LivesOne half-life leaves 50%, three leave 12.5%, ten leave less than a tenth of a percent. The formula is a single line — the part worth understanding is why the answer never reaches zero.How-toHow to Solve Stoichiometry Problems: Grams to Moles to Ratio to GramsEvery problem in the chapter is the same four moves. The mole ratio is the hinge, and it is the step students lose — worked here end to end, limiting reactant and percent yield included.