Charles's Law Calculator
V/T constant — and only in kelvin.
Work out Charles's Law. V/T constant — and only in kelvin. Temperature in kelvin, handled for you.
Final volume (L)
2
2 L → 2 L
Charles's law: at fixed pressure, V/T is constant — but only with T in kelvin. Doubling from 20 °C to 40 °C does not double the volume; doubling from 293 K to 586 K does. Using Celsius here is the classic error, and it produces an answer that looks reasonable.
How the Charles's Law Calculator works
At fixed pressure, volume is proportional to absolute temperature. Doubling from 20 °C to 40 °C does not double the volume; doubling from 293 K to 586 K does. Using Celsius here is the classic error and it produces an answer that looks reasonable.
Also known as: v1t1 = v2t2 calculator · volume temperature calculator · charles's law formula · gas expansion calculator
Frequently asked questions
What is Charles's law?
V₁/T₁ = V₂/T₂ at constant pressure, with T in kelvin. Volume is directly proportional to absolute temperature.
Why can't I use Celsius?
Because the proportionality is to absolute temperature. In Celsius the relationship has an offset, and 0 °C would imply zero volume — which is exactly where the concept of absolute zero came from.
Why does a balloon shrink in the cold?
Because the gas inside contracts in proportion to absolute temperature. Moving a balloon from 20 °C to −10 °C loses about a tenth of its volume.
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