Charles's Law describes how a gas expands when heated (and contracts when cooled) at constant pressure — volume and absolute temperature rise and fall together in direct proportion.
Charles's Law describes how a gas expands when heated (and contracts when cooled) at constant pressure — volume and absolute temperature rise and fall together in direct proportion. This calculator solves for any one of the four values.
A gas occupies 2 L at 300 K. If heated to 450 K at constant pressure, what's the new volume? Leaving V2 blank: V2 = (2×450)/300 = 3 L.
At constant pressure, the volume of a gas is directly proportional to its absolute temperature (in Kelvin): V1/T1 = V2/T2.
Charles's Law relies on absolute (Kelvin) temperature because the proportional relationship only holds when temperature is measured from absolute zero, not Celsius or Fahrenheit.
A balloon shrinking when taken from a warm room into the cold outdoors demonstrates Charles's Law — lower temperature means lower gas volume at constant pressure.