The Charles’s Law Calculator allows users to find one unknown in the equation V1/T1=V2/T2V₁/T₁ = V₂/T₂V1​/T1​=V2​/T2​, which describes the direct proportionality between the volume and temperature of a gas at constant pressure. By entering three of the four variables, the calculator computes the missing value. This tool is useful for physics students, laboratory experiments, and engineering applications to analyze how gases expand or contract with temperature changes.