Charles's Law Calculator
Enter the initial volume, initial temperature, and final temperature; by Charles's law V₁/T₁ = V₂/T₂ the tool computes the gas final volume at constant pressure.
Input Data
Results
At a glance:Enter the initial volume, initial temperature, and final temperature; by Charles's law V₁/T₁ = V₂/T₂ the tool computes the gas final volume at constant pressure.
Formula
V₁/T₁ = V₂/T₂.
Final volume V₂ = V₁·T₂/T₁ (constant pressure).
$$\dfrac{V_1}{T_1} = \dfrac{V_2}{T_2} \;\Rightarrow\; V_2 = \dfrac{V_1 T_2}{T_1}$$How to Use
- Enter the initial volume V₁, initial temperature T₁, and final temperature T₂ (in K).
- The calculator returns the final volume V₂.
Gas volume vs absolute temperature at constant pressure (V₁ = 2 L, T₁ = 273 K)
| Final T₂ (K) | °C equivalent | Final V₂ (L) | Volume change |
|---|---|---|---|
| 136.5 | −136.65 | 1.0 | halved |
| 273 | 0 | 2.0 | unchanged |
| 409.5 | 136.35 | 3.0 | 1.5× |
| 546 | 272.85 | 4.0 | doubled |
Volume is proportional to absolute temperature: doubling the temperature doubles the volume; always use kelvin.
FAQ
Why must Charles's law temperature be in kelvin?
Because volume is proportional to absolute temperature, starting from absolute zero (0 K). Using Celsius is wrong: at 0°C the volume is not zero, yet plugging 0°C into the proportionality would be absurd. Always convert K = °C + 273.15 before calculating.
How is Charles's law different from Boyle's law?
Charles's law is volume proportional to absolute temperature at constant pressure (V∝T); Boyle's law is pressure inversely proportional to volume at constant temperature (PV = constant). Together with Gay-Lussac's law they combine into the combined gas law P₁V₁/T₁ = P₂V₂/T₂.
Why does gas expand when heated?
Heating speeds up molecular motion, making molecules hit the walls more often and harder. To keep pressure constant, the gas must expand (grow volume) so the per-area collision rate returns to its original level. That is the kinetic-theory explanation behind Charles's law.
Must volume be in liters?
No — mL or m³ are fine, as long as both sides use the same unit, because the formula is a ratio and units cancel. This calculator defaults to liters; convert as needed.
Do real gases obey Charles's law exactly?
Roughly at room temperature and pressure. But at very low temperatures near liquefaction, or very high pressure, intermolecular forces and molecular volume become non-negligible and real gases deviate from ideal behavior, so Charles's law is only approximate there.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.