Gay-Lussac’s Law Calculator
💨 Gas Laws & Fluids. Use the Gay-Lussac’s law (pressure law) formula to find new pressure, starting pressure, starting temperature, new temperature: pick the value you want, type the others, and the answer updates as you go.
At constant volume, with T in kelvin.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| New pressure | kPa |
| Starting pressure | kPa |
| Starting temperature | K |
| New temperature | K |
Worked example
Find the new pressure when Starting pressure = 100 kPa, Starting temperature = 300 K, New temperature = 330 K.
Using P1/T1 = P2/T2: New pressure = 110 kPa.
Frequently asked questions
What is the formula for Gay-Lussac’s law (pressure law)?
P1/T1 = P2/T2. At constant volume, with T in kelvin.
What do the letters stand for, and what units are used?
New pressure in kPa, Starting pressure in kPa, Starting temperature in K, New temperature in K.
How do you calculate new pressure?
Put the values into P1/T1 = P2/T2. For example, with Starting pressure = 100 kPa, Starting temperature = 300 K, New temperature = 330 K, new pressure = 110 kPa.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (new pressure, starting pressure, starting temperature, new temperature) and fill in the others: it rearranges the formula for you.
