A garage door needs an opening the same size as the door, 12 inches of headroom above it for torsion springs, 3 3/4 inches of side room on each side and door height plus about 18 inches of backroom. A 16 × 7 ft double door needs a 192 × 84 in opening, 199 1/2 in of wall width and 102 in of clear depth in the garage.
Garage door size chart
Standard residential sizes, with the opening and the space around it (torsion spring, 12 in headroom):
| Door (width × height) | Opening (in) | Wall width needed (in) | Backroom (in) |
|---|---|---|---|
| 8 × 7 ft | 96 × 84 | 103 1/2 | 102 |
| 9 × 7 ft | 108 × 84 | 115 1/2 | 102 |
| 10 × 7 ft | 120 × 84 | 127 1/2 | 102 |
| 8 × 8 ft | 96 × 96 | 103 1/2 | 114 |
| 9 × 8 ft | 108 × 96 | 115 1/2 | 114 |
| 10 × 8 ft | 120 × 96 | 127 1/2 | 114 |
| 12 × 7 ft | 144 × 84 | 151 1/2 | 102 |
| 14 × 7 ft | 168 × 84 | 175 1/2 | 102 |
| 15 × 7 ft | 180 × 84 | 187 1/2 | 102 |
| 16 × 7 ft | 192 × 84 | 199 1/2 | 102 |
| 16 × 8 ft | 192 × 96 | 199 1/2 | 114 |
| 18 × 7 ft | 216 × 84 | 223 1/2 | 102 |
| 18 × 8 ft | 216 × 96 | 223 1/2 | 114 |
Single-car doors are 8, 9 or 10 ft wide, and double-car doors 12 to 20 ft, with 16 ft the most common (Precision Door, Metro Garage Doors). Seven feet is the standard height and 8 ft the upgrade. A 9 × 7 ft door is the usual single today and 16 × 7 ft the usual double.
How the garage door opening is worked out
wall width needed = door width + 2 × 3 3/4 in side room
backroom = door height + 18 in; headroom = 12 in (torsion) or 10 in (extension springs)
Rough opening for a garage door
The finished opening is the same size as the door: a 16 × 7 ft door closes against the framing of a 16 × 7 ft opening, with no deduction, per Metro Garage Doors. The jamb is framed with 2 × 6 lumber. Metro Garage Doors has you measure the opening width from inside edge to inside edge at its widest point, and the height from the floor to the underside of the header at several spots.
Headroom, side room and backroom
- Headroom is the space above the opening for the track and spring: 12 in for torsion springs and 10 in for extension springs. With an opener installed now or later, Superior Overhead Doors asks for 16 in. Low-headroom track kits cut the requirement, at a higher price.
- Side room is 3 3/4 in on each side for the vertical track, so a 16 ft door needs 199 1/2 in of wall between the side walls or obstructions.
- Backroom is the clear depth into the garage for the horizontal track and the raised door: door height plus about 18 in, per Metro Garage Doors. One installer, Superior, lists door height plus 8 in, so follow the manual that comes with your door.
Garage door header size
The opening's header carries the wall and roof above it, and its size depends on the span and the load, so this page does not pick one. A 16 ft opening spans twice a 9 ft one. Get the lumber size from the header span calculator and have your building department or an engineer confirm it before you cut or widen an opening.
The next questions
- Which spring goes with which door? Use the garage door spring calculator, which reads the width and height from this page.
- Budgeting the job: garage door replacement cost.
- Pouring the apron or floor? The concrete slab calculator works out the yards.
- Converting the measurements: feet and inches calculator.
- See every heating, cooling and plumbing calculator.