Garage Reference

Standard Garage Door Sizes — Single, Double, and RV — and How to Measure Yours Correctly

Garage doors come in more standard sizes than expected, and ordering takes five measurements rather than one. A size chart is only the starting point.

Dana Whitfield · Updated · 2 min read

Garage doors come in more standard sizes than people expect, and ordering one takes five measurements, not one. Here are the numbers, and the traps.

Standard single-car doors

The classic single door is 8 or 9 feet wide by 7 feet tall. Nine feet has become the practical default — modern trucks and SUVs with mirrors out are wider than the cars these openings were drawn for. An 8×7 opening with a full-size pickup is a mirror-folding ritual.

Standard double-car doors

Double doors run 16 feet wide by 7 feet tall, with 15-foot widths in older tracts and 18-foot doors where three-vehicle households park two abreast. If you’re pouring a new slab, the incremental cost of 18 over 16 feet is small; the daily clearance is not.

Taller doors and RV bays

Eight-foot-tall doors are increasingly common on new construction — vans, lifted trucks, and roof boxes all thank you. Dedicated RV bays run 10 to 12 feet wide and 12 to 14 feet tall. A camper’s roof AC unit is the part people forget to measure.

The five measurements that matter

  1. Opening width and height — the finished framed opening, not the old door’s panel size.
  2. Sideroom — flat wall beside each jamb; vertical track needs about 3¾ inches per side.
  3. Headroom — from the opening’s top to the lowest ceiling obstruction. Standard track wants 10–12 inches; low-headroom kits work in ~4½ but add cost. A ceiling-mounted opener rail needs its own clearance behind that.
  4. Backroom — depth into the garage: door height plus roughly 18 inches, more with an opener.
  5. The floor’s level — a sloped slab means the bottom seal needs help on one side.

What a non-standard opening really costs

Custom widths exist in 1- and 2-inch increments and cost more per door, but the expensive path is resizing the opening: reframing plus a new steel header is often four figures before the door arrives. If your opening is within an inch or two of a standard size, buy standard and let the stop molding absorb the difference.

Measure twice — the door is the one part of the house that moves every day and forgives nothing.