Boyle’s Law Calculator
Calculate final pressure or volume for a gas at constant temperature using Boyle’s law (P₁V₁ = P₂V₂).
How it works
- 1Select whether to solve for final pressure (P₂) or final volume (V₂).
- 2Enter the initial pressure P₁ (kPa), initial volume V₁ (L), and the known final quantity.
- 3The calculator applies P₁V₁ = P₂V₂ instantly — results update as you type.
Use cases
- Predicting how pressure changes when a gas syringe is compressed in a lab.
- Calculating a balloon’s new volume as it rises to lower-pressure altitude.
- Verifying pressure–volume relationships in pneumatic systems.
Frequently asked questions
What is Boyle’s law?
For a fixed amount of gas at constant temperature, pressure and volume are inversely proportional: P₁V₁ = P₂V₂. Doubling the pressure halves the volume, and vice versa.
Why doesn’t the unit matter as long as I am consistent?
Because Boyle’s law is a ratio — the units cancel on both sides of P₁V₁ = P₂V₂. This calculator uses kPa and litres, so keep both pressures in kPa and both volumes in L.
Can you show a worked example?
A gas occupies 2 L at 100 kPa and is compressed to 1 L at the same temperature. P₂ = P₁V₁ ÷ V₂ = (100 × 2) ÷ 1 = 200 kPa — halving the volume doubled the pressure.
Related tools
See all →Calculate average velocity from displacement and time, in metric or imperial units.
Calculate average velocity from displacement and time, or from initial and final speeds.
Calculate average acceleration from initial velocity, final velocity, and elapsed time.
Calculate average acceleration from change in velocity and time interval in metric or imperial units.