Boyle's Law Calculator
Calculate final pressure when the volume of a fixed amount of gas changes at constant temperature. Enter the known pressure and volumes to calculate the unknown value.
Boyle's law
Find final pressure at constant temperature.
Enter positive values. Temperatures must be in Kelvin and pressures must be absolute, not gauge pressure.
Your answer will appear here
Enter your known values and select Calculate to see the result, formula, and solution steps.
How Boyle's law works
Boyle's law describes the inverse relationship between pressure and volume for a fixed amount of gas at constant temperature. When volume decreases, pressure increases; when volume increases, pressure decreases.
P₁V₁ = P₂V₂
Assumptions and conditions
- The temperature remains constant.
- The amount of gas remains constant.
- Pressure is absolute pressure, not gauge pressure.
- Initial and final volumes use the same unit.
Frequently asked questions
What is Boyle's law?
Boyle's law states that pressure and volume are inversely proportional for a fixed amount of gas at constant temperature.
What happens when volume decreases?
If temperature and amount of gas stay constant, decreasing volume increases pressure.
Which units can I use?
Use consistent pressure units and the same volume unit for both states. This calculator displays kPa and litres.
What is the Boyle's law formula?
The formula is P₁V₁ = P₂V₂. Rearranging it gives P₂ = P₁V₁/V₂.
How to use this calculator
- Enter the initial absolute pressure.
- Enter the initial volume and final volume.
- Keep the pressure and volume units consistent.
- Select Calculate result to obtain the final pressure.
Boyle's law equation
For a fixed amount of gas at constant temperature, the initial pressure multiplied by the initial volume equals the final pressure multiplied by the final volume. The equation can be rearranged to find an unknown pressure or volume.