What is the rough opening for a 36 inch door?
38″ wide × 82½″ tall
The short answer
For a standard 36 × 80 inch interior prehung door, frame the rough opening, the hole between the studs, 38 inches wide and 82½ inches tall. The extra 2 inches of width and 2½ inches of height leave room for the jambs and shims. That is about 965 × 2096 mm. Always confirm with the door maker's chart.
How it is worked out
- Door slab: 36″ × 80″
- Add 2″ to the width: 38″
- Add 2½″ to the height: 82½″
Other sizes and options
| Door size | Rough opening |
|---|---|
| 24″ × 80″ | 26″ × 82½″ |
| 28″ × 80″ | 30″ × 82½″ |
| 30″ × 80″ | 32″ × 82½″ |
| 32″ × 80″ | 34″ × 82½″ |
| 34″ × 80″ | 36″ × 82½″ |
| 36″ × 80″ | 38″ × 82½″ |
What can change the amount?
Only replacing the door in its existing frame? Skip the rough opening: measure the old door itself, edge to edge, and order that size. Exterior doors and 96 inch tall doors follow their own charts, so check the maker's figures, and measure the framed opening at the top, middle and bottom.
Worked out with common rules of thumb and code minimums, for planning. Check the product label, the maker's instructions and your local building code before you buy or build. More detail in the Window and door sizes guide.