Garage door clearance and fit checker
Measure your opening and enter three clearances. You get a pass or fail for each track type that applies.
Enter headroom, sideroom, and backroom
Clearance minimums are from Clopay's published track clearance table: standard lift headroom 12 in (12 in radius) or 14.25 in (15 in radius), sideroom 4.5 in, backroom door height plus 16 in; low headroom front mount 9 in, 4.5 in, plus 23 in; rear mount 4.5 in, 7.5 in, plus 30 in; vertical lift sideroom 5 in; roof pitch sideroom 4.5 in and backroom plus 25 in.
How this calculator works
A garage door needs space above the opening (headroom), beside it (sideroom), and behind it (backroom) for the track and hardware. The minimums depend on the track. For a standard lift with 12 inch radius track that is 12 inches of headroom, 4.5 inches on each side, and the door height plus 16 inches of backroom. Low-headroom, vertical lift, and roof-pitch tracks have their own numbers.
Enter your three clearances and the tool compares each one with the published minimum and shows how much spare room or shortfall you have.
Frequently asked questions
How much headroom does a garage door need?
A standard lift track needs about 12 inches with 12 inch radius track and 14.25 inches with 15 inch radius track. Low-headroom tracks need as little as 4.5 to 9 inches.
What if I do not have enough headroom?
Look at a low-headroom track kit, either front mount or rear mount. They trade a bit of backroom or sideroom for less headroom.
How much space do I need behind the garage door?
For standard lift, the door height plus 16 inches. For a 7 foot door, that is 100 inches. Low-headroom and roof-pitch tracks need more.
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Last updated October 2026. Reviewed by the Fix or Hire editorial team. Estimates only, not a quote.