Free garage door calculator: headroom, backroom and side room
Get a garage door opening's margins against the maker's figures in seconds, free and without an account. One opening at a time: its width and height, then what you measured above it, behind it and on each side. Pick the maker and track to fill the figures it prints, or type your maker's: the calculation gives the door area, the margin at each place and the weatherstrip to order. In imperial or metric.
Garage door clearances: what the makers print (reference)
Figures read in the makers' measuring and installation guides. They disagree: your door maker's have the last word.
| Headroom | Backroom | Side room | |
|---|---|---|---|
| Garaga | Torsion: 10, 12 or 15 in for a 10, 12 or 15 in radius; low headroom 5 in rear mounted, 8 in front mounted; extension: 8 1/2 or 10 in; 2 in more with an opener | Door height + 24 in, + 40 in with an opener | At least 6 in from the jamb to the wall; 12 in between two doors |
| Clopay | 10 in for extension springs, 12 in for torsion, more with an opener | Door height + 18 in, more with an opener | 3 3/4 in each side, 5 1/2 in for EZ-SET |
| Amarr | 15 in for most doors with an opener | Door height + 18 in, + 50 in with an opener | 3 3/4 in each side |
| Wayne Dalton 8000 | 11 in for a 12 in radius, 6 in low headroom, 2 1/2 in more with a motor | A total of 102 in, 125 in motor operated, for a 6 to 7 ft door on a 12 in radius: a total, not added to the height | Not printed |
Sources: Garaga, installation manual; Clopay, how to measure; Amarr, how to measure; Wayne Dalton, Model 8000
How it is calculated
Door area = opening width x height: the door is ordered at the opening size (Garaga, Clopay, Amarr). Headroom margin = headroom measured - headroom the maker asks. Backroom the maker asks = door height + the maker's allowance. Backroom margin = backroom measured - backroom asked. Side room margin = the narrower side - the side room asked. Weatherstrip = width + 2 x height (the header and both jambs). The same formulas as the garage door survey template. Picking a maker fills only the figures it prints, with or without an opener; the others stay yours to type.
Example: a double door with an opener
From our template page's demo: a 16 x 7 ft double door, torsion springs on a 12 in radius track and an opener, from a maker that follows Garaga's table: 14 in of headroom, the door height plus 40 in of backroom, 6 in on each side. Measured: 15 in of headroom, 20 ft of backroom, 8 in on the left and 6.5 in on the right. The door is 112 sq ft; the headroom margin is 1 in; the maker asks 10.33 ft of backroom, which leaves 9.67 ft; the narrower side leaves 0.5 in; and the header and jambs take 30 ft of weatherstrip.
The whole job in MesuPro
Garage door survey
Opening by opening: door size, headroom, backroom, side room, track, springs, opener and weatherstrip.
You get: Door area
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