PV
Gas Law Calculator

Ideal Gas Law Calculator

Solve PV = nRT for any variable. Instant live calculation, full unit intelligence, and clear step-by-step reasoning.

Result
1.0006248 atm
Using formula: P = nRT / V
1.Given: n = 1 mol, T = 273.15 K, V = 22.4 L
2.Convert to base units: n = 1.000000 mol, T = 273.1500 K, V = 22.400000 L
3.Use R = 0.08205746 L·atm/(mol·K)
4.P (atm) = (n × R × T) / V = (1.000000 × 0.08205746 × 273.1500) / 22.400000
5.P (atm) = 1.0006248 atm
6.Convert to atm: 1.0006248 atm
Presets:

The Ideal Gas Law Formula

PV = nRT

Pressure × Volume = moles × Gas constant × Temperature

The Ideal Gas Law is one of the most useful equations in chemistry and physics. It relates the pressure (P), volume (V), amount of substance (n), and absolute temperature (T) of an ideal gas through the gas constant R.

This calculator lets you solve for any one of the four variables while giving you complete freedom over units. All conversions are performed with high precision so you never lose accuracy when switching between atm, kPa, torr, psi, liters, m³, °C, K, etc.

How to use this calculator

  1. Select which variable you want to solve for (P, V, n, or T).
  2. Enter the known values and choose the appropriate units.
  3. The result updates instantly with a full step-by-step solution.
  4. Use the presets for common conditions (STP, 25 °C, SI units).

Common values of the gas constant R

ValueUnitsTypical use
0.082057L·atm/(mol·K)Most chemistry problems
8.3145J/(mol·K)SI / physics
62.364L·torr/(mol·K)When pressure is in torr
0.083145L·bar/(mol·K)When pressure is in bar

Standard conditions

  • STP (Standard Temperature and Pressure): 0 °C (273.15 K) and 1 atm. One mole of ideal gas occupies 22.414 L.
  • SATP (Standard Ambient Temperature and Pressure): 25 °C (298.15 K) and 1 bar. Molar volume ≈ 24.79 L.

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Combined Gas Law →Boyle’s Law →Charles’s Law →van der Waals →