Charles's Law Calculator
Enter any three of initial volume, initial temperature, final volume and final temperature, and this calculator finds the fourth using Charles's Law, V1/T1 = V2/T2, at constant pressure. Temperatures are converted to Kelvin for the math.
How to use the Charles's Law calculator
- Pick which quantity you want to solve for.
- Choose Kelvin or Celsius and enter the other three values.
- Read the missing value, solved from V1/T1 = V2/T2.
Examples
Solve for final volume
V1 = 2, T1 = 300 K, T2 = 600 K
V2 = 4
Celsius input
V1 = 2, T1 = 27 C, T2 = 327 C
V2 = 3.999
Frequently asked questions
What is Charles's Law?
Charles's Law states that at constant pressure the volume of a fixed amount of gas is directly proportional to its absolute temperature, so V1/T1 = V2/T2.
Why must temperature be in Kelvin?
The law only holds on an absolute scale. Celsius values are converted by adding 273.15 to get Kelvin before solving, then converted back.
What volume units can I use?
Any consistent unit works because only the ratio matters. Use the same unit for both V1 and V2.
How many values do I need to enter?
Exactly three of the four. From any three of V1, T1, V2 and T2 the fourth is fully determined.
What if a temperature comes out at or below absolute zero?
That is unphysical, so the calculator rejects any temperature that converts to 0 K or below.
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