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Ideal Gas Law Calculator
Solve one missing value in the ideal gas equation. Enter any three values, choose units, and calculate the fourth in the browser.
How do I use the ideal gas law calculator?
Use PV = nRT, where P is absolute pressure, V is volume, n is amount of gas in moles, T is absolute temperature in kelvin and R = 8.314462618 J/(mol·K). Enter exactly three positive values and leave the value to solve blank. Unit conversions are handled automatically.
Frequently asked questions
How do I use the ideal gas law calculator?
Use PV = nRT, where P is absolute pressure, V is volume, n is amount of gas in moles, T is absolute temperature in kelvin and R = 8.314462618 J/(mol·K). Enter exactly three positive values and leave the value to solve blank. Unit conversions are handled automatically.
Are my gas-law values uploaded?
No. The calculation runs locally in this browser. Values you enter are not uploaded or saved by this tool.
What is the ideal gas law equation?
The equation is PV = nRT. Use absolute pressure, volume, amount of gas in moles and temperature in kelvin with R = 8.314462618 J/(mol·K). This calculator converts supported units to consistent SI units before solving.
Can I enter Celsius or pressure in atmospheres?
Yes. Choose degrees Celsius or kelvin and units including Pa, kPa, MPa, bar, atm, torr or psi. Celsius is converted to absolute temperature; temperatures at or below absolute zero are rejected.
Is the ideal gas law accurate for every gas?
No. It is an approximation for gas behaviour. Real gases can depart from the model, especially near condensation, at high pressure or at low temperature. This tool does not assess gas hazards, containers or safe operating conditions.