To calculate the evacuation time for a vacuum chamber, all of the above factors must be taken into account.
For a quick estimate, however, it is often sufficient to perform a segmented use of the simplified evacuation time equation.
This formula gives you the ideal evacuation time, but it will likely be longer depending on the specific contributing factors. It’s also important to note that these results can only be regarded as a reasonable estimate for rough vacuums. Fine vacuum pressure ranges from 1000mbar to approx. 0.1mbar.