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Boyle's Law describes how the pressure and volume of a fixed amount of gas relate to each other when temperature stays constant: as one goes up, the other goes down, in exact proportion. This calculator solves for whichever value is missing given the other three.
How it works
Enter any 3 of the 4 values — initial pressure, initial volume, final pressure, and final volume — and leave the one you want to solve for blank. The calculator applies P₁V₁ = P₂V₂ to find the missing value.
- Enter pressure 1 (P₁) — leave blank to solve for this.
- Enter volume 1 (V₁) — leave blank to solve for this.
- Enter pressure 2 (P₂) — leave blank to solve for this.
- Enter volume 2 (V₂) — leave blank to solve for this.
- Click Calculate to see your results.
Examples
Compressing a gas
A gas at 2 atm and 4 L is compressed to 1 L at constant temperature — its new pressure is 8 atm, since pressure and volume are inversely proportional.
Who should use it
- Chemistry and physics coursework on gas laws.
- Estimating pressure/volume changes in simple constant-temperature scenarios.
Industry applications
- Chemistry and physics education
- Basic pneumatics and gas-handling estimation
Advantages
- Simple, exact relationship for constant-temperature gas problems.
- Widely taught starting point for understanding gas behavior.
Limitations
- Doesn't apply if temperature changes during the process — use the Combined Gas Law for that case.
Common mistakes to avoid
- Mixing units mid-calculation (e.g. entering one volume in liters and the other in milliliters) — convert everything to the same unit first.
- Forgetting that Boyle's Law only holds at constant temperature — if temperature also changes, use the Combined Gas Law instead.
Best practices
- Double-check that temperature is genuinely constant between the two states before applying this law.
- Keep pressure and volume in consistent units throughout.
Tips
- If you know three of the four values, you always have enough information to solve for the fourth — you never need all four.