Thermodynamics calculation lab

Ideal Gas Law Calculator

Solve pressure, volume, number of moles, or temperature using the ideal gas law with automatic conversion between common scientific and engineering units.

Automatic unit conversion Solve four variables Celsius, Fahrenheit and Kelvin

Gas particle chamber

Stable

Pressure P = nRT/V

Volume V = nRT/P

Moles n = PV/RT

Temperature T = PV/nR

Ideal Gas Law Workbench

Select the variable you want to calculate.

Solve for gas pressure

Calculate Pressure

Enter volume, amount of gas, and absolute temperature to calculate gas pressure.

P = nRT ÷ V

Thermodynamic output

Calculated pressure

1 atm

Pressure for 1 mole at 273.15 K in 22.414 L.

In pascals 101,325 Pa

In kilopascals 101.325 kPa

In bar 1.01325 bar

In psi 14.696 psi

Formula trace


                                P = (1 mol × 8.314462618 × 273.15 K) ÷ 0.022414 m³

How it works

Solve the Ideal Gas Law in Four Steps

The calculator converts each value into SI units, applies the correct form of PV = nRT, and returns the result in practical units.

Select a variable

Choose pressure, volume, moles, or temperature as the unknown.

Enter known values

Add the three available gas properties required by the formula.

Choose units

Mix common pressure, volume, amount, and temperature units.

Review the answer

See the main result, converted values, and full formula trace.

Gas law fundamentals

Understanding the Ideal Gas Law

The ideal gas law connects pressure, volume, temperature, and the amount of gas in a single equation. It is commonly written as PV = nRT.

The equation assumes gas particles have negligible volume and do not attract or repel one another. Real gases behave most like ideal gases at relatively low pressure and high temperature.

Pressure measures particle collisions More frequent and energetic collisions with the container walls create higher pressure.

Temperature must be absolute Gas law calculations require Kelvin or another absolute temperature scale.

Moles represent gas quantity The amount of gas is measured in moles and directly affects pressure or volume.

Ideal Gas Law Formulas

Ideal gas equation PV = nRT P is pressure, V is volume, n is moles, T is temperature.

Calculate pressure P = nRT ÷ V Divide the product of moles, R, and temperature by volume.

Calculate volume V = nRT ÷ P Divide the product of moles, R, and temperature by pressure.

Calculate moles n = PV ÷ RT Divide pressure times volume by R times temperature.

Calculate temperature T = PV ÷ nR Temperature is first calculated in kelvin.

Gas constant used R = 8.314462618 J/(mol·K) The calculator converts all values into SI units first.

Practical applications

Where Ideal Gas Law Calculations Are Used

The ideal gas equation is widely used in chemistry, physics, engineering, laboratory work, and environmental science.

Chemistry Experiments

Estimate gas volume, amount, pressure, or temperature in laboratory reactions.

Process Engineering

Analyze gases moving through tanks, pipelines, and processing systems.

Atmospheric Science

Study relationships between air pressure, volume, temperature, and density.

Gas Storage

Estimate how pressure changes inside cylinders and storage containers.

Thermodynamics

Explore how gases respond to changes in pressure, volume, and temperature.

Science Education

Practice gas law problems with automatic unit conversion and formula tracing.

Frequently asked questions

Ideal Gas Law Calculator FAQs

Common questions about PV = nRT, gas units, absolute temperature, and ideal gas assumptions.

What is the ideal gas law?

The ideal gas law is PV = nRT. It relates pressure, volume, amount of gas, absolute temperature, and the universal gas constant.

What variables can this calculator solve?

The calculator can solve for pressure, volume, number of moles, or temperature when the other three values are known.

Which gas constant does the calculator use?

The calculator uses R = 8.314462618 joules per mole kelvin after converting pressure, volume, and temperature into SI units.

Why must temperature be in Kelvin?

Gas law equations require an absolute temperature scale. Kelvin starts at absolute zero, so temperature remains physically meaningful in proportional calculations.

Can I enter temperature in Celsius or Fahrenheit?

Yes. You can enter Celsius, Fahrenheit, Kelvin, or Rankine. The calculator automatically converts the value to kelvin before solving.

Can I use liters and atmospheres?

Yes. The calculator supports liters, milliliters, cubic meters, cubic feet, atmospheres, pascals, kilopascals, bar, psi, and torr.

When does the ideal gas law become less accurate?

It becomes less accurate at very high pressure or low temperature, where gas particles interact more strongly and occupy a significant amount of space.

Can the result be used for real gases?

The result is a useful approximation for many gases, especially at moderate pressure and higher temperature. Precision work may require a real-gas equation of state.

Scientific note: The ideal gas law is an approximation. Real gases can deviate from ideal behavior at high pressure, low temperature, or near condensation conditions.