Dalton's Law Calculator
💨 Gas Laws & Fluids. Use the Dalton's law formula to find total pressure, partial 1 (n₂), partial 2 (o₂), partial 3: pick the value you want, type the others, and the answer updates as you go.
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 |
|---|---|
| Total pressure | kPa |
| Partial 1 (N₂) | kPa |
| Partial 2 (O₂) | kPa |
| Partial 3 | kPa |
Worked example
Find the total pressure when Partial 1 (N₂) = 79.1 kPa, Partial 2 (O₂) = 21.2 kPa, Partial 3 = 1 kPa.
Using Ptotal = Σ Pi: Total pressure = 101.3 kPa.
Frequently asked questions
What is the formula for Dalton's law?
Ptotal = Σ Pi.
What do the letters stand for, and what units are used?
Total pressure in kPa, Partial 1 (N₂) in kPa, Partial 2 (O₂) in kPa, Partial 3 in kPa.
How do you calculate total pressure?
Put the values into Ptotal = Σ Pi. For example, with Partial 1 (N₂) = 79.1 kPa, Partial 2 (O₂) = 21.2 kPa, Partial 3 = 1 kPa, total pressure = 101.3 kPa.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (total pressure, partial 1 (n₂), partial 2 (o₂), partial 3) and fill in the others: it rearranges the formula for you.
