LabReadyTools

Ideal Gas Law Calculator

P V = n R T, R = 8.314462618 J/(mol·K)

Solve the ideal gas law PV = nRT for pressure, volume, amount of substance or temperature.

Inputs

Absolute pressure, not gauge pressure.

Convert to a mass afterwards with the molecular weight calculator.

Result

0.04034 mol

P = 1 bar, V = 1 L, n = 0.04034 mol, T = 298.15 K.

Calculation

  1. Ideal gas law

    P V = n R T, R = 8.314462618 J/(mol·K)

  2. Converted to SI

    Pa, m³, mol, K

    P = 100000 Pa, V = 0.001 m³, n = 0.0403395 mol, T = 298.15 K

  3. Rearranged for n

    n = P V / (R T)

    n = 100000 × 0.001 / (8.314462618 × 298.15)

    n = 0.0403395 mol

  4. Converted back to your unit

    0.04034 mol

Inputs

Pressure
1 bar
Volume
1 L
Amount
0.04034 mol
Temperature
298.15 K

This is the ideal gas approximation. Real gases deviate at high pressure, at low temperature and near condensation; a compressibility factor or a real-gas equation of state is needed there.

The calculation is always performed in SI (Pa, m³, mol, K) with R = 8.314462618 J/(mol·K), so unit systems are never mixed.

Temperatures are converted to absolute temperature before use; values at or below 0 K are rejected.

Values used in SI units

P
100000 Pa
V
0.001 m³
n
0.04034 mol
T
298.15 K

R = 8.31446261815324 J/(mol·K)

About this calculator

The ideal gas law links the pressure, volume, amount of substance and absolute temperature of a gas through the universal gas constant R. Enter any three quantities and the fourth follows. Everything is converted to SI units — pascals, cubic metres, moles and kelvin — before the calculation, and the converted values appear in the steps.

Temperature must be absolute. Celsius input is converted with T(K) = θ(°C) + 273.15, and temperatures at or below absolute zero are rejected rather than producing a meaningless answer.

Real gases deviate from ideal behaviour at high pressure and near their condensation point, where a compressibility factor or a real-gas equation of state is needed. No standard temperature and pressure is assumed: if you want molar volume at STP or NTP, enter that temperature and pressure explicitly.

LabReadyTools is provided as a calculation aid. Users remain responsible for verifying calculations, units, chemical compatibility, experimental procedures and applicable safety requirements before laboratory use.

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