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Chemistry

Combined Gas Law Calculator

Calculate a new gas volume when absolute pressure and Kelvin temperature change at fixed gas amount.

Explicit units and model assumptionsLocal calculations with worked examples
Chemistry workspace
Chemistry workspace

Check the units, concentration basis and assumptions before interpreting the result.

See the method

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Your chemistry result

Your result

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Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter initial absolute pressure, initial volume, initial temperature, final absolute pressure, final temperature.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

V2 = P1 × V1 × T2 ÷ (P2 × T1), from P1V1/T1 = P2V2/T2. Gas amount stays constant while volume responds to both pressure and temperature.

A WORKED EXAMPLE

Using initial absolute pressure = 100 kPa, initial volume = 10 L, initial temperature = 300 K, final absolute pressure = 200 kPa, final temperature = 330 K, the result is 5.5 L. Change these example inputs to match your task; use the method above to check each step.

Understanding your result

No. Add 273.15 to a Celsius reading before using these Kelvin fields; ratios of Celsius readings do not describe the gas law.

What to keep in mind

The gas amount is fixed and ideal behavior is assumed. All temperatures must be Kelvin. Educational calculation only; use validated procedures for laboratory work.

Reference: OpenStax Chemistry 2e — chemical quantities and models

Common questions

Can I enter Celsius in the temperature fields?

No. Add 273.15 to a Celsius reading before using these Kelvin fields; ratios of Celsius readings do not describe the gas law.

Are my inputs uploaded?

No. This calculation runs in your browser without an account or an external API.

Methodology maintained by ClarityKit. How these tools are built and checked.