What is the ideal gas law?
The ideal gas law calculator helps you work with the relationship between pressure, volume, temperature, and the amount of gas. In its most common form, it’s written as:
PV = nRT
- P = pressure
- V = volume
- n = moles of gas
- T = temperature (Kelvin)
- R = gas constant
When can you use it?
You can use the ideal gas law as a good approximation for many gases under conditions that aren’t extremely high pressure or extremely low temperature. It’s widely used in chemistry and basic engineering problems, especially when you’re comparing how one variable changes while the others stay the same.
How the calculator works
Pick which variable you want to solve for (pressure, volume, temperature, or moles). Then enter the other known values. The calculator will:
- Convert your inputs into consistent units (including converting °C to K when needed).
- Apply the algebra needed to rearrange PV = nRT.
- Convert the result back into the unit you selected.
Quick tips for accurate results
- Temperature: The ideal gas law uses Kelvin. If you enter Celsius, the calculator converts it for you.
- Units matter: Use the unit dropdowns so the math stays consistent.
- Watch significant figures: Your final answer is only as precise as your inputs.
Try it now
Use the tool above to get an instant answer. Whether you’re doing homework, planning an experiment, or just curious about gas behavior, this ideal gas law calculator makes the process quick and clear.
Common rearrangements you’ll see
| To solve for… | Use… |
|---|---|
| Pressure (P) | P = nRT / V |
| Volume (V) | V = nRT / P |
| Temperature (T) | T = PV / (nR) |
| Moles (n) | n = PV / (RT) |
Friendly reminder: The ideal gas law is a model. For real gases, especially at extreme conditions, deviations can happen—but for many everyday problems, it’s a great starting point.