Garage door rough opening
Pick the door size. You get the opening to frame, the finished opening the door has to cover, the height to the underside of the header, and the headroom, side room and back room the hardware needs — worked both ways, because that is exactly where the figures published online disagree.
Inputs
Optional: measure what you have and the results check it. Leave a box blank to skip it.
Result
| What | You have | Needs |
|---|
Garage door rough opening chart
Every nominal door size sold, with the opening to frame under both jamb details. The finished opening — the hole the door actually covers — is the door size in every row, which is the one figure every manufacturer agrees on.
| Door (ft) | Finished opening | Rough opening jambs on the face | Rough opening 2x jambs inside |
|---|---|---|---|
| 8 × 7 | 8' 0" × 7' 0" | 8' 0" × 7' 0" | 8' 3" × 7' 1-1/2" |
| 9 × 7 | 9' 0" × 7' 0" | 9' 0" × 7' 0" | 9' 3" × 7' 1-1/2" |
| 10 × 7 | 10' 0" × 7' 0" | 10' 0" × 7' 0" | 10' 3" × 7' 1-1/2" |
| 12 × 7 | 12' 0" × 7' 0" | 12' 0" × 7' 0" | 12' 3" × 7' 1-1/2" |
| 15 × 7 | 15' 0" × 7' 0" | 15' 0" × 7' 0" | 15' 3" × 7' 1-1/2" |
| 16 × 7 | 16' 0" × 7' 0" | 16' 0" × 7' 0" | 16' 3" × 7' 1-1/2" |
| 18 × 7 | 18' 0" × 7' 0" | 18' 0" × 7' 0" | 18' 3" × 7' 1-1/2" |
| 8 × 8 | 8' 0" × 8' 0" | 8' 0" × 8' 0" | 8' 3" × 8' 1-1/2" |
| 9 × 8 | 9' 0" × 8' 0" | 9' 0" × 8' 0" | 9' 3" × 8' 1-1/2" |
| 10 × 8 | 10' 0" × 8' 0" | 10' 0" × 8' 0" | 10' 3" × 8' 1-1/2" |
| 12 × 8 | 12' 0" × 8' 0" | 12' 0" × 8' 0" | 12' 3" × 8' 1-1/2" |
| 16 × 8 | 16' 0" × 8' 0" | 16' 0" × 8' 0" | 16' 3" × 8' 1-1/2" |
| 18 × 8 | 18' 0" × 8' 0" | 18' 0" × 8' 0" | 18' 3" × 8' 1-1/2" |
| 10 × 10 | 10' 0" × 10' 0" | 10' 0" × 10' 0" | 10' 3" × 10' 1-1/2" |
| 12 × 10 | 12' 0" × 10' 0" | 12' 0" × 10' 0" | 12' 3" × 10' 1-1/2" |
| 12 × 12 | 12' 0" × 12' 0" | 12' 0" × 12' 0" | 12' 3" × 12' 1-1/2" |
| 14 × 14 | 14' 0" × 14' 0" | 14' 0" × 14' 0" | 14' 3" × 14' 1-1/2" |
Widths of 8 to 10 ft are the single-car sizes and 12 to 18 ft the doubles; 9 to 14 ft heights are RV and oversize special orders (Clopay, “What Are the Standard Garage Door Sizes”). Custom doors are made in between, and the same two rules apply to any size.
Headroom by spring type and track radius
Headroom is measured from the top of the finished opening to the ceiling or the underside of the joists. Three manufacturers publish different numbers for the same hardware, so all three are here; frame to the largest, because it costs nothing before the header goes in.
| Springs | Track radius | Clopay | Amarr | Garaga | Frame to | Frame to, with opener |
|---|---|---|---|---|---|---|
| Extension | 10" | — | — | 8-1/2" | 8-1/2" | 10-1/2" |
| Extension | 12" | 10" | 12" | 10" | 12" | 15" |
| Extension | 15" | 12" | 15" | — | 15" | 18" |
| Torsion | 10" | — | — | 10" | 10" | 12" |
| Torsion | 12" | 12" | 12" | 12" | 12" | 15" |
| Torsion | 15" | 14" | 15" | 15" | 15" | 18" |
Clopay Table 3-A, plus its “about 3 in more” for an opener; Amarr Table 1, which gives the same figure for both spring types and lists the with-opener figure directly; Garaga Fig. 5, plus its “add 2 in” for an opener, and the only one of the three to publish a 10 in radius. A dash means that maker does not publish that combination. Overhead Door gives a single minimum of 12 in for every door.
Minimum ceiling height by door height
The finished opening plus the headroom the hardware needs, with an automatic opener. This is the figure that decides whether a taller door fits at all.
| Door height | Ext. 12" | Ext. 15" | Tor. 12" | Tor. 15" |
|---|---|---|---|---|
| 6' 6" | 7' 9" | 8' 0" | 7' 9" | 8' 0" |
| 7' 0" | 8' 3" | 8' 6" | 8' 3" | 8' 6" |
| 7' 6" | 8' 9" | 9' 0" | 8' 9" | 9' 0" |
| 8' 0" | 9' 3" | 9' 6" | 9' 3" | 9' 6" |
| 9' 0" | 10' 3" | 10' 6" | 10' 3" | 10' 6" |
| 10' 0" | 11' 3" | 11' 6" | 11' 3" | 11' 6" |
| 12' 0" | 13' 3" | 13' 6" | 13' 3" | 13' 6" |
| 14' 0" | 15' 3" | 15' 6" | 15' 3" | 15' 6" |
Columns are the spring type and track radius from the table above, using the largest of the published with-opener figures. The 10 in radius is left out: only Garaga publishes it.
The one dimension everyone agrees on
The finished opening — the hole the closed door covers, measured between the jambs — equals the nominal door size. A 9 x 7 door needs a finished opening 9 ft 0 in wide and 7 ft 0 in high. Wayne Dalton’s measuring guide says to measure the “exact finished opening width” and that it “should equal the same size as the existing door”. Clopay and Amarr say the same thing in different words. Get that wrong and the door either will not cover the hole or will not fit between the jambs.
Why the rough opening figures online disagree
Search for this and you will be told two different things: that the rough opening equals the door size, and that it is 3 in wider and 1-1/2 in taller. Both are right. They describe two different jamb details, and almost nobody says which one they mean.
Jambs on the wall face
This is what the manufacturers’ own instructions assume. The structural opening is framed at the door size, the 2x jambs are fastened to the inside wall face around the opening, and the stop moulding laps the opening on the outside. Garaga’s manual gives the clearest version, with a worked example: “Make sure that the size of the opening matches the size of the door” — a 9 x 7 door “needs an opening of 9 feet wide by 7 feet high”. Clopay’s steel residential instructions say it on Fig. 3-A: “Rough opening (minus stop mold) = same size as door”. Amarr’s Step 1: “approximately the same size as the door”. Overhead Door’s Series 190/290/490 instructions: “Opening should be the same width as the length of the door section.” Five makers, one answer.
2x jambs let into the framing
Here the framer leaves the opening oversize and the jambs are set inside it, so the framing has to grow by the thickness of the jamb: 1-1/2 in on each side for dressed 2x lumber, and 1-1/2 in at the head only, because the slab is the sill. That gives the door size plus 3 in wide and plus 1-1/2 in high. DASMA’s TDS-156 and TDS-161 both call for vertical jambs of minimum 2x6 lumber but neither publishes a rough opening size, which is the clue: this is a framing choice, not a dimension handed down by the industry.
Both details end at the same finished opening. So the question to ask your installer is not “how big is the rough opening” but “are the jambs going on the face or inside the framing?” If nobody has decided yet, frame it at the door size and put the jambs on the face: that is the detail the instructions in the box with the door are written for.
Headroom, side room and back room
Headroom is the space above the finished opening for the curved track and the springs. Torsion springs mount on a shaft above the door and need more of it than extension springs, and a bigger track radius needs more again. An opener adds 2 in (Garaga) to about 3 in (Clopay) at the centre of the ceiling for the rail and the motor head; frame to the 3.
Side room is from the edge of the opening to the nearest wall, on the inside. The published minimums run from 3-1/4 in (Overhead Door) through Clopay’s “minimum 3-3/4 in ... on each side of door on interior wall surface” for the vertical track and minimum 4-1/2 in on each side above the opening where a torsion spring is anchored, to Amarr’s 5-1/2 in and Garaga’s “minimum space between the door jamb and wall: 6 in”. Frame to 6 in where you can: it costs nothing at framing and it fits every maker’s hardware. Two doors side by side need a centre post of at least 11 in (Amarr) or 12 in (Garaga); make it 12.
Back room is how far the horizontal tracks run into the garage. Clopay asks for “at least 18 in more than height of garage door”, Garaga for the door height plus 24 in. With an opener, Garaga publishes the door height plus 40 in — 10 ft 4 in for a 7 ft door — for the rail and motor head; Clopay says an opener needs more without saying how much. Openers vary, so check the one you buy against that figure. A jackshaft opener mounts beside the door and needs no rail at all.
Low headroom and tight garages
If the ceiling is short, the fix comes from the door maker, not the framing. Garaga’s rear-mounted low-headroom track runs in 5 in of headroom (7 in with an opener), and its front-mounted torsion version in 8 in. A jackshaft opener removes the rail and most of the back room. Both are catalogue options; neither is something to improvise on site.
What this does not do
It sizes the opening, not the structure above it. A garage door opening is almost always in a bearing wall, and the header over it is the part that needs a real number: the header size calculator gives the 2x header and jack studs from the IRC tables, and will tell you plainly that nothing in those tables spans 16 ft, which is why wide garage door headers are LVL or glulam sized from the maker’s tables. In high-wind and coastal areas the door itself is a pressure-rated assembly and the jamb fastening is engineered — that is what DASMA TDS-161 is for, and it says a registered professional engineer should confirm the connection. Masonry and steel-framed openings use different jamb details again.
To count the framing around the opening, kings and jacks included, use the stud calculator.
Questions
What is the rough opening for a 9x7 garage door?
The finished opening is 9 ft 0 in by 7 ft 0 in, the door size. Frame it 9' 0" wide by 7' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 9' 3" by 7' 1-1/2" where 2x jambs are let into the framing.
What is the rough opening for an 8x7 garage door?
Finished opening 8 ft 0 in by 7 ft 0 in. Frame it 8' 0" wide by 7' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 8' 3" by 7' 1-1/2" where 2x jambs are let into the framing.
What is the rough opening for a 16x7 garage door?
Finished opening 16 ft 0 in by 7 ft 0 in. Frame it 16' 0" wide by 7' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 16' 3" by 7' 1-1/2" where 2x jambs are let into the framing. The header over a 16 ft opening is the real problem, not the opening: no 2x header in IRC Table R602.7(1) spans it.
What is the rough opening for a 16x8 garage door?
Finished opening 16 ft 0 in by 8 ft 0 in. Frame it 16' 0" wide by 8' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 16' 3" by 8' 1-1/2" where 2x jambs are let into the framing.
What is the rough opening for a 9x8 garage door?
Finished opening 9 ft 0 in by 8 ft 0 in. Frame it 9' 0" wide by 8' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 9' 3" by 8' 1-1/2" where 2x jambs are let into the framing.
What is the rough opening for a 10x8 garage door?
Finished opening 10 ft 0 in by 8 ft 0 in. Frame it 10' 0" wide by 8' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 10' 3" by 8' 1-1/2" where 2x jambs are let into the framing.
What is the rough opening for an 8x8 garage door?
Finished opening 8 ft 0 in by 8 ft 0 in. Frame it 8' 0" wide by 8' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 8' 3" by 8' 1-1/2" where 2x jambs are let into the framing.
What is the rough opening for a 10x10 garage door?
Finished opening 10 ft 0 in by 10 ft 0 in. Frame it 10' 0" wide by 10' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 10' 3" by 10' 1-1/2" where 2x jambs are let into the framing. At this height check the ceiling first: with torsion springs on 12 in track and an opener it needs about 11 ft 3 in of ceiling.
What is the rough opening for a 12x12 garage door?
Finished opening 12 ft 0 in by 12 ft 0 in. Frame it 12' 0" wide by 12' 0" high where the jambs go on the wall face, which is what the installation manuals assume, or 12' 3" by 12' 1-1/2" where 2x jambs are let into the framing. A 12 ft door is an RV or oversize special order and needs about 13 ft 3 in of ceiling with an opener.
Should the rough opening be bigger than the garage door?
Not the way the manufacturers write it. Garaga says a 9 x 7 door needs an opening 9 ft wide by 7 ft high; Clopay says the rough opening minus the stop moulding is the same size as the door; Amarr and Overhead Door say the same. The “3 in wider” advice you will find online, Google’s own summary included, describes the other detail: framing oversize so 2x jambs can be let into the opening. Decide which detail you are using before the wall goes up, because the finished opening has to come out at the door size either way.
How much headroom does a garage door need?
For a standard residential door on 12 in track: 12 in with torsion springs, by Clopay, Amarr and Garaga alike. With extension springs Clopay and Garaga say 10 in and Amarr 12 in. Add 2 to 3 in for an automatic opener, so frame to 15 in. On 15 in track it is 14 to 15 in, or 18 in with an opener. With less than that, a low-headroom track runs in as little as 5 in (Garaga).
How high is the header above the floor for a garage door?
The underside of the header sits at the top of the rough opening. Framed at the door size that is the door height exactly — 7 ft 0 in for a 7 ft door — and with 2x jambs inside the framing it is 1-1/2 in higher. The header itself then needs its own headroom above it for the springs and track.
How much side room does a garage door need?
The published minimums run from 3-1/4 in (Overhead Door) and 3-3/4 in (Clopay, for the vertical track, with 4-1/2 in above the opening where a torsion spring is anchored) to 5-1/2 in (Amarr) and 6 in (Garaga). Frame to 6 in each side where the wall allows it. Two doors side by side need a centre post of 12 in.
How deep does a garage need to be for the door to open?
Without an opener, the door height plus 24 in (Garaga; Clopay says plus 18 in) — 9 ft for a 7 ft door. With an opener, Garaga gives the door height plus 40 in: 10 ft 4 in for a 7 ft door and 11 ft 4 in for an 8 ft door. A jackshaft opener mounts at the side and needs no rail, so it needs no extra depth.
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