Combined Gas Law Calculator
Solve P₁V₁/T₁ = P₂V₂/T₂ for any missing value.
Enter your values
Choose one of: Final pressure P₂, Final volume V₂, Final temperature T₂.
Enter the initial pressure p₁ in atm.
Enter the initial volume v₁ in L.
Enter the initial temperature t₁ in °C.
Enter the final pressure p₂ in atm.
Enter the final volume v₂ in L.
Enter the final temperature t₂ in °C.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Answer
- 1.25155 L
- Final pressure
- 2 atm
- Final volume
- 1.25155 L
- Final temperature
- 100 °C (373.15 K)
- Initial temperature in Kelvin
- 298.15 K
- PV/T constant
- 0.006708
Quick answer
The combined gas law links pressure, volume and temperature for a fixed amount of gas: P₁V₁ ÷ T₁ = P₂V₂ ÷ T₂, with temperature in Kelvin.
P₁V₁ ÷ T₁ = P₂V₂ ÷ T₂
At a glance
| What it does | Solve P₁V₁/T₁ = P₂V₂/T₂ for any missing value. |
|---|---|
| Category | Chemistry |
| Inputs needed | Solve for, Initial pressure P₁, Initial volume V₁, Initial temperature T₁, Final pressure P₂, Final volume V₂, Final temperature T₂ |
| Main output | Answer |
| Formula | P₁V₁ ÷ T₁ = P₂V₂ ÷ T₂ |
| Cost | Free — no sign-up, no download |
How to use the Combined Gas Law Calculator
- 1Pick which final value you are solving for.
- 2Enter the initial pressure, volume and temperature in °C.
- 3Enter the two known final values — the third is calculated.
Inputs explained
- Solve for
- Choose one of: Final pressure P₂, Final volume V₂, Final temperature T₂.
- Initial pressure P₁(atm)
- Enter the initial pressure p₁ in atm.
- Initial volume V₁(L)
- Enter the initial volume v₁ in L.
- Initial temperature T₁(°C)
- Enter the initial temperature t₁ in °C.
- Final pressure P₂(atm)
- Enter the final pressure p₂ in atm.
- Final volume V₂(L)
- Enter the final volume v₂ in L.
- Final temperature T₂(°C)
- Enter the final temperature t₂ in °C.
Worked example
Using the values the calculator loads with:
Inputs
- Solve forFinal volume V₂
- Initial pressure P₁1 atm
- Initial volume V₁2 L
- Initial temperature T₁25 °C
- Final pressure P₂2 atm
- Final volume V₂1 L
- Final temperature T₂100 °C
Results
- Answer1.25155 L
- Final pressure2 atm
- Final volume1.25155 L
- Final temperature100 °C (373.15 K)
- Initial temperature in Kelvin298.15 K
- PV/T constant0.006708
Frequently asked questions
Why must temperature be in Kelvin?
The gas laws are ratios, and only an absolute scale makes 'twice the temperature' mean twice the molecular energy.
What if the gas amount changes?
Then you need the ideal gas law PV = nRT, which includes moles explicitly.
What do I need to enter into the Combined Gas Law Calculator?
Just 7 values: solve for, initial pressure p₁, initial volume v₁, initial temperature t₁, final pressure p₂, final volume v₂, final temperature t₂. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Combined Gas Law Calculator work out the answer?
The combined gas law links pressure, volume and temperature for a fixed amount of gas: P₁V₁ ÷ T₁ = P₂V₂ ÷ T₂, with temperature in Kelvin. It applies the formula P₁V₁ ÷ T₁ = P₂V₂ ÷ T₂ and shows the working so you can check each step by hand.
Is the Combined Gas Law Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.