Calculating your final pressure (p2) is straightforward once you know the Boyle's Law formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Boyle's Law Calculator.
What is Boyle's Law?
The Boyle's Law calculation tells you your final pressure (p2) from a few simple inputs. The figure you are solving for here is the final pressure (p2).
The Boyle's Law formula
The core formula is:
Final pressure (P2) = Initial pressure (P1) × Initial volume (V1) ÷ Final volume (V2)Here is what each input means:
- Initial pressure (P1) — a number. Example: 1.
- Initial volume (V1) — a number. Example: 10.
- Final volume (V2) — a number. Example: 5.
How to calculate it step by step
- Write down the initial pressure (p1) (for example, 1).
- Write down the initial volume (v1) (for example, 10).
- Write down the final volume (v2) (for example, 5).
- Apply the formula above to get your final pressure (p2).
- Double-check the result with the Boyle's Law Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Initial pressure (P1) | 1 |
| Initial volume (V1) | 10 |
| Final volume (V2) | 5 |
| Final pressure (P2) | 2.000 |
With initial pressure (p1) of 1, initial volume (v1) of 10 and final volume (v2) of 5, the final pressure (p2) works out to 2.000.
Example 2
With initial pressure (p1) of 2, initial volume (v1) of 10 and final volume (v2) of 5, the final pressure (p2) works out to 4.000.
| Result | Value |
|---|---|
| Final pressure (P2) | 4.000 |
Example 3
With initial pressure (p1) of 5, initial volume (v1) of 10 and final volume (v2) of 5, the final pressure (p2) works out to 10.000.
| Result | Value |
|---|---|
| Final pressure (P2) | 10.000 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Boyle's Law Calculator does it instantly, for free, with the formula and a worked example built in.
Related calculators
Continue exploring science calculators with these tools: Impulse Calculator, Elastic Potential Energy Calculator, Thermal Expansion Calculator, Buoyancy Force Calculator, RPM to Linear Speed Calculator.