Ideal Gas Law Calculator

PV = nRT | Solve for Pressure, Volume, Moles, or Temperature

Result
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📝 Step-by-step solution
Select variable to solve and enter known values
💡 R = 8.314 J/(mol·K) | Temp MUST be in Kelvin (K = °C + 273.15)

📖 How to Use This Ideal Gas Law Calculator

1
Select what you want to calculate - Pressure (P), Volume (V), Moles (n), or Temperature (T).
2
Enter the known values - For pressure: enter volume, moles, and temperature.
3
Click "Calculate" - Get your result with step-by-step solution.
4
Important: Temperature must be in Kelvin (K = °C + 273.15).

🧪 The Ideal Gas Law (PV = nRT)

The ideal gas law is a fundamental equation in chemistry and physics that describes the behavior of an ideal gas. It combines Boyle's Law, Charles's Law, Avogadro's Law, and Gay-Lussac's Law into a single relationship.

📊 Ideal Gas Law Formulas

Pressure: P = nRT / V
Volume: V = nRT / P
Moles: n = PV / RT
Temperature: T = PV / nR

🔬 Gas Constant R Values

💡 Standard Conditions (STP)

❓ Frequently Asked Questions

What is an ideal gas vs real gas?
An ideal gas follows PV=nRT perfectly. Real gases deviate at high pressure and low temperature. The ideal gas law is accurate for most gases at room temperature and atmospheric pressure.
Why must temperature be in Kelvin?
Kelvin is an absolute temperature scale starting at absolute zero. The ideal gas law requires absolute temperature because pressure and volume are directly proportional to absolute temperature.
Which R value should I use?
Use R = 8.314 for pressure in Pascals (Pa) and volume in cubic meters (m³). Use R = 0.0821 for pressure in atmospheres (atm) and volume in liters (L).
How do I convert Celsius to Kelvin?
Kelvin = Celsius + 273.15. For example, 25°C = 298.15 K.