Ideal Gas Law Calculator

Free Ideal Gas Law Calculator solves PV = nRT for any of the four variables in your chosen units.

904.9K uses Updated · 2026-05-12 Runs locally · zero upload
AD

How to Use Ideal Gas Law Calculator

The Ideal Gas Law Calculator instantly returns whichever of P, V, n, or T you need.

  1. Pick the unknown — P, V, n, or T.
  2. Enter the other three — Use any supported unit.
  3. Read the result — The Ideal Gas Law Calculator returns the unknown in your chosen unit.

Formula & Theory - Ideal Gas Law Calculator

PV = nRT
R = 8.314462618 J/(mol·K)

Rearrangements:
P = nRT / V
V = nRT / P
n = PV / (RT)
T = PV / (nR)
SymbolMeaning
PAbsolute pressure (Pa)
VVolume (m³)
nAmount of substance (mol)
TAbsolute temperature (K)

Assumptions and Limits

  • Ideal gas; particles have no volume and no intermolecular forces.
  • For real gases at high P or low T, expect deviations.

Use Cases for Ideal Gas Law Calculator

  • Chemistry & physics homework — Solve PV=nRT in seconds.
  • Lab calculations — Determine moles from observed P, V, T.
  • Engineering checks — Estimate gas pressure or volume in vessels.

The Ideal Gas Law Calculator is the all-in-one tool for PV = nRT problems.

Frequently asked questions about Ideal Gas Law Calculator

What is the ideal gas law?

PV = nRT relates pressure, volume, moles, and absolute temperature of a gas. The Ideal Gas Law Calculator rearranges it to solve for any variable.

What value of R is used?

R = 8.314462618 J/(mol·K). The Ideal Gas Law Calculator converts pressure to Pa, volume to m³, moles to mol, and temperature to K internally.

When does the ideal gas law break down?

At very high pressure or very low temperature, real gases deviate from PV = nRT. Use a compressibility factor or equation of state in those regimes.

Is my data stored?

No. All calculations happen in your browser; nothing is sent to a server.