Van Der Waals Equation Calculator
💨 Gas Laws & Fluids. Use the Van der Waals equation formula to find pressure, volume, amount, temperature, a, b: pick the value you want, type the others, and the answer updates as you go.
Default a, b: CO₂.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Pressure | atm |
| Volume | L |
| Amount | mol |
| Temperature | K |
| a | L²·atm/mol² |
| b | L/mol |
Worked example
Find the pressure when Volume = 22.4 L, Amount = 1 mol, Temperature = 273 K, a = 3.59 L²·atm/mol², b = 0.0427 L/mol.
Using (P + an²/V²)(V - nb) = nRT: Pressure = 0.99482 atm.
Frequently asked questions
What is the formula for Van der Waals equation?
(P + an²/V²)(V - nb) = nRT. Default a, b: CO₂.
What do the letters stand for, and what units are used?
Pressure in atm, Volume in L, Amount in mol, Temperature in K, a in L²·atm/mol², b in L/mol.
How do you calculate pressure?
Put the values into (P + an²/V²)(V - nb) = nRT. For example, with Volume = 22.4 L, Amount = 1 mol, Temperature = 273 K, a = 3.59 L²·atm/mol², b = 0.0427 L/mol, pressure = 0.99482 atm.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (pressure, volume, amount, temperature, a, b) and fill in the others: it rearranges the formula for you.
