Framing rough opening sizes are really quite simple. Just add 2″ to the width of the actual door size. You should add 2-1/2″ to the height of the actual door. This will give you room to space the door frame off of the sub-floor.
How To Frame A Door Opening
Two Wall Framing Methods for Window Rough Openings
Frequently Asked Questions
How much larger should a rough opening be for an exterior door?
The rough opening should be at least ¾ inch wider and ⅜ inch taller than the door frame.