Charles's Law Calculator (V₁/T₁ = V₂/T₂)
At constant pressure, gas volume is directly proportional to absolute temperature (in Kelvin). Find the new volume after a temperature change.
How to use this charles's law calculator
- Convert temperatures to Kelvin: K = °C + 273.15.
- Enter initial volume and temperature.
- Enter the final temperature.
- Example: 1 L at 0°C (273.15 K) heated to 100°C (373.15 K) → 1.366 L.
Formula
V₁/T₁ = V₂/T₂ at constant pressure. V₂ = V₁ × T₂ ÷ T₁. Temperature MUST be in Kelvin.
About the Charles's Law Calculator
Charles's Law explains why hot-air balloons fly and why bread rises faster in a warm oven. The direct proportionality V ∝ T (in Kelvin) is elegant: double the absolute temperature, double the volume.
Practically: a car tyre at 20°C (293 K) vs 40°C (313 K) shows a 7% volume increase — which manifests as slightly higher tyre pressure since the tyre constrains volume. Temperature effects on gas are significant even at everyday temperature changes.
Frequently asked questions
+Why must temperature be in Kelvin?
Kelvin is an absolute scale — 0 K is where molecular motion theoretically stops. Using Celsius would give nonsensical negative volumes. Charles's Law requires V=0 at T=0 K.
+Everyday example?
Hot-air balloons: heating air increases its volume, lowering density below surrounding air, providing lift. A basketball left in a hot car expands; on a cold morning tyres look deflated.
+Who was Jacques Charles?
Jacques Charles (1746–1823), a French physicist and balloonist, discovered this relationship in 1787 — the same year he made the first hydrogen balloon flight.