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Rough opening sizes for doors and windows
Typical — check the unit
Typical rough openings for prehung interior doors by width and height, and the usual allowance for windows.
These are common figures, not a rule: the manufacturer's spec for the unit you are installing comes first. Check the unit.
Verify with your local code and AHJ. Reference only, no warranty.
Prehung interior door, width
| Door | Rough opening | |
|---|---|---|
| 24″ | 2′ 0″ | 26″ |
| 28″ | 2′ 4″ | 30″ |
| 30″ | 2′ 6″ | 32″ |
| 32″ | 2′ 8″ | 34″ |
| 36″ | 3′ 0″ | 38″ |
Door width plus 2″.
Prehung interior door, height
| Door | Rough opening | |
|---|---|---|
| 6′ 8″ | 80″ | 82 1/2″ |
| 8′ 0″ | 96″ | 98 1/2″ |
Window
| Width | unit + 1/2″ |
| Height | unit + 1/2″ |
Questions
What is the rough opening for a 32″ door?
Typically 34″ wide for a prehung interior door, and 82 1/2″ tall for a standard 6′ 8″ door. Check the unit.
What is the rough opening for a 36″ door?
Typically 38″ wide for a prehung interior door. Check the unit.
How much bigger than the window is the rough opening?
Typically unit + 1/2″ on the width and unit + 1/2″ on the height. Check the unit's spec.