Gas Law Calculator

Calculate gas properties using PV=nRT. Free online ideal gas law calculator.

The Gas Law Calculator solves the ideal gas equation PV = nRT for any unknown variable. Enter pressure, volume, temperature, or moles, and solve for the missing value. Essential for chemistry, physics, and engineering applications involving gas behavior under various conditions.

Common use cases

  • Chemistry gas problems
  • Engineering gas systems
  • Scuba diving calculations
  • Balloon and airship design
  • Pressure vessel calculations

How to use

  1. Select which variable to solve for
  2. Enter the known values with units
  3. Choose appropriate units for each
  4. Click calculate for the result
  5. View the calculation with R value used

FAQ

What is the ideal gas law?

PV = nRT, relating pressure (P), volume (V), moles (n), and temperature (T) with gas constant R.

What is R?

The gas constant: 8.314 J/(mol·K), 0.0821 L·atm/(mol·K), or 62.36 L·mmHg/(mol·K), depending on units.

Must temperature be in Kelvin?

Yes, gas law calculations require absolute temperature (Kelvin). Convert °C to K by adding 273.15.

When does the ideal gas law fail?

At high pressures and low temperatures, real gases deviate from ideal behavior. Use van der Waals equation for better accuracy.