// physics › Gas Laws
Use Boyle's Law P1 V1 = P2 V2 at constant temperature; choose what to solve for, and check a container's burst limit.
P₁V₁ = P₂V₂
If you squeeze a trapped gas into a smaller space, its pressure goes up. Give it more room and the pressure drops. As long as the temperature stays the same, pressure and volume always trade off against each other.
Pick what you want to find in the 'Solve for' box — P₁, V₁, P₂ or V₂ — then type in the other three values. The calculator works out the missing one using P₁V₁ = P₂V₂. The '1' is before and the '2' is after.
Say a gas starts at pressure 100 and volume 2, and you squeeze it to volume 1. What is the new pressure? Pressure times volume stays equal: 100 × 2 = P₂ × 1, so 200 = P₂. The pressure doubled because the volume halved.
The gas law itself never stops — but a real container can. If you choose a balloon, syringe or steel cylinder, the calculator checks whether your final pressure goes past what that container can hold, and warns you if it would burst. Those burst values are rough, for illustration — not exact engineering numbers.
Any units you like — but keep them the same on both sides. If you measure pressure in pascals, use pascals for both pressures. If volume is in litres, use litres for both. Because it is a ratio, the units cancel out. (Note: the container burst check assumes the pressures are in pascals.)
Squeeze a sealed packet of chips and it gets firmer — you shrank the volume so the pressure rose. Pump a bike tyre and the trapped air pushes back harder as it compresses. Scuba divers rely on it too, as the air in their gear changes volume with depth.