When you check your engine oil, the car should not be running. It is usually best to have your engine be cold, so you do not burn yourself while interacting with the engine.
If you were just driving, let your engine cool for five to ten minutes before checking the oil level. However, some automakers request your car be warm when you check the oil. To do this, you’ll want to run your engine, then turn it off and let it sit for a minute before popping the hood. Check your owner’s manual to discover what temperature your engine should be at when getting under the hood.