Installation & Measurement
Opening Size
Opening size is the clear width and height of a garage door opening. Width is measured between the jamb faces. Height is measured from the floor to the underside of the header. It determines what size door to order. Doors are typically made 2 inches wider and 2 inches taller than the opening.
Opening size is the clear dimension of the garage door opening. Amarr breaks it into two measurements. Opening height is the distance from the garage floor to the top of the opening. Opening width is the distance between the left and right jambs.
These numbers are the starting point for every door order. The door is built larger than the opening so it can close against the stop molding and seal all the way around. Standard practice is to order 2 inches wider and 2 inches taller than the opening. This overlap covers the jamb face and the stop molding on each side.
For example: a two-car opening that measures 15 feet 10 inches wide and 6 feet 11 inches tall gets a 16-foot by 7-foot door. The extra 2 inches on each side lets the weatherstrip press fully against the jamb.
Opening size is not the same as rough opening. The rough opening is the framed hole in the wall before any finish material goes in. The jambs and header installed inside the rough opening shrink the clear dimension down to the usable opening size.
Getting the measurement right matters. Doors are made to specific nominal sizes. An error means a return shipment or a custom order. Both cost more and take longer.
Track hardware quantities also depend on opening size. Vertical track length, for example, is set by the opening height.
Related terms
Jamb
A jamb is the vertical framing member on each side of a garage door opening. Learn how the track, flag bracket, and weatherstrip all attach to the jamb during installation.
View termTrajectory
Trajectory is the arc the top garage door section sweeps in front of the opening as it rises from vertical to horizontal travel. Learn how it affects driveway and opener clearance.
View termDouble Low Headroom Track
Double low headroom track uses two parallel overhead tracks to open a garage door with very limited clearance above the header. Learn when it is needed and how it works.
View termPeople also ask
Common questions related to opening size.
What is the difference between garage door rough opening and door size?
The rough opening is the framed hole in the wall, measured between the inside edges of the framing.
Read full answerWhat size garage door do I need?
What size garage door do you need? Single doors run 8 to 9 feet wide, doubles 16 feet, both 7 feet tall. Learn how to measure your opening the right way.
Read full answerHow do I measure my garage door spring's wire size?
Measure 10 coils of the spring with a ruler, then 20 coils, and compare both lengths to a wire size chart.
Read full answerHow much does a garage door spring cost by size?
Garage door spring replacement costs $150 to $350 for a pair of torsion springs installed, or $75 to $200 for extension springs.
Read full answerCurrent offers
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