During an IFR flight, how do you calculate your altitude if your altimeter is set correctly?

When flying under Instrument Flight Rules (IFR), the key focus is ensuring that you maintain a safe and accurate altitude to comply with air traffic control instructions and to ensure separation from other aircraft. If your altimeter is set correctly according to current atmospheric pressure, the best practice is to maintain the indicated altitude while operating. This ensures that you are flying at the altitude that air traffic controllers expect and that conforms to the altimeter setting for the area you are flying in.

Maintaining the indicated altitude means that you should be constantly referencing the altimeter to ensure your altitude is correct as per the regional local altimeter settings. This is crucial for safety, as fluctuations in atmospheric pressure can cause altitude variations that may not be reflected in your actual altitude above sea level. By focusing on the altitude shown on your altimeter, you make certain that you are flying at the altitude you intend to be, keeping you within safe flying parameters and adhering to any altitude restrictions or guidance stipulated by air traffic control.

In this context, while ground reference adjustments or monitoring the vertical speed indicator might provide useful data during flight, they do not replace the need to maintain the indicated altitude as shown on your altimeter. Properly setting and maintaining the altimeter reading is fundamental to safe IFR