Calculator Inputs
Choose the missing variable, enter the other three values, and review the computed gas state.
Formula used
Boyle's law states that pressure and volume are inversely related for a fixed mass of gas at constant temperature.
Main equation: P1 × V1 = P2 × V2
Rearranged forms:
- P1 = (P2 × V2) ÷ V1
- V1 = (P2 × V2) ÷ P1
- P2 = (P1 × V1) ÷ V2
- V2 = (P1 × V1) ÷ P2
All pressure values are normalized to pascals and all volumes to cubic meters before calculation, which keeps mixed-unit inputs consistent.
How to use this calculator
- Select the missing variable you want to calculate.
- Enter the other three known values.
- Choose matching units for each pressure and volume field.
- Select output units and decimal precision.
- Press Calculate Result to show the answer below the header and above the form.
- Review ratios, normalized checks, and export the output if needed.
Example data table
| Case | P1 | V1 | P2 | V2 | Missing Variable | Result |
|---|---|---|---|---|---|---|
| Lab Compression | 120 kPa | 2.5 L | 200 kPa | 1.5 L | None | PV constant = 300 Pa·m³ equivalent |
| Syringe Example | 101.3 kPa | 60 mL | ? | 35 mL | P2 | 173.66 kPa |
| Expansion Test | 2 atm | 1.2 L | 1.1 atm | ? | V2 | 2.18 L |
Frequently asked questions
1. What does Boyle's law describe?
It describes the inverse relationship between gas pressure and volume when temperature and gas quantity remain constant. When volume drops, pressure rises proportionally.
2. Can I use different units together?
Yes. The calculator converts pressure values to pascals and volume values to cubic meters internally, so mixed units can still produce a correct result.
3. Why must all inputs be positive?
Absolute pressure and physical volume cannot be zero or negative in this model. Positive values keep the gas state realistic and the inverse relation meaningful.
4. Does this calculator include temperature effects?
No. Boyle's law assumes constant temperature. If temperature changes significantly, you should use a combined gas law or ideal gas law calculator instead.
5. What is the PV consistency check?
It compares P1×V1 and P2×V2 after unit normalization. Small differences usually come from rounding, while large differences suggest input or unit mistakes.
6. What does compression ratio mean here?
Compression ratio is V1 divided by V2. A value above one means the gas occupies less final volume than initial volume, indicating compression.
7. When should I use absolute pressure?
Use absolute pressure for rigorous physics work, especially when gauge pressure might distort the actual gas state. Consistent pressure basis improves reliability.
8. Can I export the calculated result?
Yes. After calculation, you can download a CSV summary or generate a PDF report containing the solved variable, state values, and derived ratios.