Ideal Gas Law Calculator
Use the ideal gas relationship for quick thermodynamic estimates in SI units.
Pressure101.182 kPa
Pressure0.9986 atm
How this tool works
PV = nRT, so P = nRT/V with R = 8.314462618 J/(mol·K).
Example
One mole near 298 K occupying about 0.0245 m³ is close to atmospheric pressure under the ideal-gas approximation.
Common questions
When does the ideal gas law become inaccurate?
At high pressures, low temperatures or near phase changes, real-gas effects can require compressibility factors or an equation of state.
Can I enter Celsius directly?
No. Temperature must be absolute Kelvin because the gas-law proportionality uses an absolute temperature scale.