This Combined Gas Law Calculator can help you estimate either the pressure, temperature or the volume of gas by combining the Charles, Boyle and Gay-Lussac laws. Below the form you can find more information on this topic.

Instruction: Please input five fields from the six below!

Pressure 1 (p1):*
Volume 1 (V1):*
Temperature 1 (T1):*
Pressure 2 (p2):*
Volume 2 (V2):*
Temperature 2 (T2):*

How does this combined gas law calculator work?

This tool can calculate any from volume, pressure or temperature gas changes by considering the combined gas law which states that the ratio between the product of the pressure & volume and the temperature of a gas based system remains constant.

Combined gas law formula:

PV/T = k


k = constant

P = pressure

V = Volume

T = temperature

In order to compute the changes in temperature, pressure or volume a sample gas may suffer in certain conditions, the combined gas law can be written in the form detailed within the next rows:


Depending on the variable to be estimated the user should input the other five fields out of the six available. This combined gas law calculator is supporting various measurement units, as explained here:

Volume is by default in m3

From: To: m3
l 0.001
ml 0.000001
ft3 0.02831685
in3 0.00001638706                 

Pressure is by default in Pa:

From: To: Pa
KPa 1000
Bar 100000
atm 101325.01
mmHg 133.32238157895                 
mbar 100

The temperature is by default expressed in Kelvin but can also be specified in Celsius or in Fahrenheit, as the calculator applies the following rules to convert it to Kelvin:

From °C to K = t°C + 273.15

From °F to K = (t°F + 459.67) * 5/9

22 Jun, 2015