Guide
What is a standard garage door size?
There is no single standard, and anyone telling you there is has not measured many garages. There are four sizes that cover most American houses, and then everything else.
There is no standard, in the sense of a published specification that manufacturers have to meet. What people mean by "standard" is what builders kept ordering, and that has moved twice in living memory.
A 16x7, drawn to scale. Two normal cars side by side. The most common double door in America.
| Size | Rough opening | Steel, installed |
|---|---|---|
| 16x7 | 16'0" × 7'0" | $3,240 |
| 10x10 | 10'0" × 10'0" | $5,970 |
| 8x7 | 8'0" × 7'0" | $3,170 |
| 9x7 | 9'0" × 7'0" | $3,170 |
| 10x8 | 10'0" × 8'0" | $3,170 |
| 16x8 | 16'0" × 8'0" | $3,240 |
| 12x10 | 12'0" × 10'0" | $6,390 |
| 12x12 | 12'0" × 12'0" | $6,390 |
| 10x7 | 10'0" × 7'0" | $3,170 |
| 18x7 | 18'0" × 7'0" | $3,240 |
| 18x8 | 18'0" × 8'0" | $3,240 |
| 12x7 | 12'0" × 7'0" | $3,170 |
| 20x10 | 20'0" × 10'0" | $6,390 |
| 20x8 | 20'0" × 8'0" | $6,390 |
| 20x12 | 20'0" × 12'0" | $6,390 |
Guide ranges, checked September 2026. Prices move — get it in writing.
In full
Four sizes cover most American houses. A single garage is 8x7 on anything built before roughly 1970 and 9x7 on almost everything since. A double is 16x7 on houses from the 1970s onwards, and 16x8 on a great deal of what has gone up in the last twenty years. If you are standing in front of an opening and guessing, those four are where to start — and 16x7 alone accounts for more doors than any other size in the country.
The reason they became standard is not engineering. It is that a builder putting up two hundred houses orders one door two hundred times, and a supplier who sells that size a thousand times a week keeps it on the shelf. So the size that was convenient became the size that was cheap, and the size that was cheap became the size everybody has. That is also why stepping outside those four costs more and takes longer — not because the door is harder to make, but because nobody has one in stock.
What moved is height. Cars got taller before they got wider: a pickup with a rack, an SUV with a roof box, anything with a raised suspension. Seven feet of opening stopped being enough for a normal family vehicle, and builders in truck country went to eight. Width moved less, because a garage's width is set by the footprint of the house and adding two feet of door means adding two feet of building.
The practical consequence is that "standard" tells you what is likely, not what you have. A house that has been extended, a garage that was converted and converted back, or an opening somebody widened after scraping the car once will not match any of the four. Measure the finished opening — the hole in the wall, not the door leaf and not the driveway — before you order anything.
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