Boyle's Law Calculator
P₁V₁ = P₂V₂ for a gas at constant temperature.
Quick answer
- Formula: P₁ × V₁ = P₂ × V₂ (constant temperature and amount of gas)
- Worked example — Initial pressure (P₁): 2.00000 (full example below).
Boyle's Law Calculator
| Initial pressure (P₁) | 2.00000 |
| Initial volume (V₁) | 3.00000 |
| Final pressure (P₂) | 3.00000 |
| Final volume (V₂) | 2.00000 |
Compressing a gas from 3 L to 2 L at constant temperature raises its pressure from 2 to 3 (in whatever pressure unit you started with).
Boyle's law says that for a fixed amount of gas at constant temperature, pressure and volume are inversely proportional: squeeze the volume in half and the pressure doubles.
Choose the value to solve for and enter the other three — leave the solved value at 0, it is ignored. Pressure and volume units just need to be consistent between state 1 and state 2.
The formula
Worked example
Compressing a gas from 3 L to 2 L at constant temperature raises its pressure from 2 to 3 (in whatever pressure unit you started with).
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
What must stay constant for Boyle's law?
Temperature and the amount of gas. If the gas heats up during compression, pressure rises more than Boyle's law predicts — use the ideal gas calculator for changing temperatures.
Do I need absolute or gauge pressure?
Absolute pressure. Gauge readings (like a tyre gauge) are relative to atmospheric pressure — add about 1 atm (101.3 kPa) to convert before calculating, if precision matters.
Category: Science calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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