Boyle's Law Calculator

About this calculator

Boyle's law states that for a fixed amount of ideal gas at constant temperature, pressure and volume are inversely proportional: P₁V₁ = P₂V₂. Compress the gas into a smaller volume and its pressure rises proportionally; let it expand and pressure falls — a relationship discovered by Robert Boyle in 1662 and one of the founding gas laws that later combined into the ideal gas law (PV = nRT).

Chemistry and physics students use it as an entry point into gas behavior, but it's also practically important for scuba divers (understanding how air in the lungs and tank expands or compresses with depth, which is why divers are taught never to hold their breath while ascending), and for engineers working with compressed gas systems, syringes, and pneumatics. Enter the initial pressure and volume plus either the final pressure or final volume to solve for the other.