This Charles Law Calculator estimates the pressure or the temperature change of gas if you provide 3 out of the 4 variables in the Charles equation where the volume (v) is constant. You can get the formulas used below the form.

Instruction: Please input three fields from the four below!

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

How does this Charles Law Calculator work?

This form can help in calculating any change in pressure or temperature of gas by the Charles Law which states that when the volume of a sample gas is constant, its pressure is proportional with its temperature:

Charles Law formula: P1/T1= P2/T2

Each of the variables in the equation can be determined if the other 3 variables are given:

-  P1 and P2 formulas:

P1 = P2*T1/T2

P2 = P1*T2/T1

-  T1 and T2 equations:

T1 = P1*T2/P2

T2 = P2*T1/P1

P1 is the initial pressure;

T1 is the initial temperature;

P2 is the pressure changed;

T2 is the temperature changed;

Assumption: Volume (v) and Mass (m) stay constant.

This calculator allows choosing between multiple units depending on the variable type as it is based on these conversion rates:

- For Pressure the default unit in the SI is  Pa:


To: Pa











- The temperature is by default set up to Kelvin but it can be expressed in Celsius or in Fahrenheit as well. The formulas applied to convert to Kelvin are:

From °C to K = t°C + 273.15

From °F to K = (t°F + 459.67) * 5/9

22 Jun, 2015