Practical guide · 6 min read
Ideal Gas Law: Units and Worked Examples
Rearrange PV = nRT safely and keep units consistent.
The ideal gas law connects four state variables through a universal gas constant.
Choose a consistent R
Use R = 8.314462618 when pressure is in pascals, volume in cubic meters, and temperature in kelvin.
Rearrange symbolically
Isolate the unknown before inserting numbers. This exposes division mistakes early.
Check physical plausibility
Pressure, absolute temperature, volume, and amount cannot be negative in ordinary gas-law problems.
Put it into practice
Try the related calculator
Use the method above with an interactive tool that keeps the equation and units visible.
Open calculatorEditorial note
This guide is educational. Examples are deliberately compact and cannot cover every model, course convention, or laboratory condition. See our methodology for how formulas and examples are reviewed.