Garage door sizes and how to measure your opening

What are the standard garage door sizes?

Common residential examples include 8x7 and 9x7 single doors and 16x7 double doors, with width listed first. Other widths and heights are available. The opening and the selected model determine which size can be ordered.

For scale, a 9x7 label means 9 ft wide by 7 ft high. Garaga’s size guide gives examples for single and double openings; it is not a survey of Ottawa homes. The table below is a starting point, not a complete size list or a vehicle-fit guarantee. Also confirm the door type: sectional doors and other overhead-opening designs can have different mounting and clearance requirements.

What size is a single garage door?

Single-door examples include widths of 8 ft or 9 ft and heights of 7 ft or 8 ft. Measure the actual opening and your vehicle, including mirrors and roof accessories. A size label alone does not confirm that a vehicle will clear the opening.

Extra width can make entry easier, but the existing opening may limit your choice. Measure roof racks, boxes and other accessories with the vehicle as it will be driven inside. Compare that envelope with the clear opening when the door is fully open. A high ceiling alone does not make an opening taller. Once the size is confirmed, review the door materials, which decide how the door holds up in an Ottawa winter. Appearance is a separate choice made after that, covered under door styles.

What size is a double garage door?

A 16 ft wide door is a common double-door example. Some models also offer 18 ft widths and other sizes. Check the opening, usable parking space and vehicle clearance rather than choosing from the number of cars alone.

The selected door assembly determines its weight, springing and hardware requirements. The opener must suit that assembly; width alone does not select the motor. For an attached garage, compare the insulated-door options alongside the opening measurements. Ask for an installed quote for the actual model and scope.

How do you measure for a new garage door?

Record the finished opening width and height at several points, then measure headroom, side room on both sides and backroom. Keep every reading and note obstructions. Use the selected door, track and opener drawings to confirm the order and required clearances.

1. 1Opening width. Measure between the finished jambs near the top, middle and bottom. Record all three widths in inches and note any difference.
2. 2Opening height. Measure from the finished floor to the underside of the opening at the left, centre and right. Record every height and note an uneven floor or header.
3. 3Headroom. Record the space above the opening to the lowest obstruction. Compare it with the selected door, spring, track and opener drawings.
4. 4Side room. Measure usable space on each side separately, noting obstructions at different heights. Check track, bracket and operator requirements against their drawings.
5. 5Backroom. Measure into the garage along the proposed track and opener paths. Note beams, ducts, lights and storage, then check the equipment drawings.

Garaga asks for opening measurements at several positions. Keep those readings rather than sending only the widest or highest one. They help the installer spot an opening that is out of square. These preliminary measurements do not replace the final site check.

Headroom, backroom and side room you need

Headroom, side room and backroom requirements depend on the selected door, track, spring system and opener. Measure to the lowest obstruction, including a beam or duct, then compare those measurements with the manufacturer's installation drawing for that combination.

Our headroom and high-lift guide explains the different track arrangements. A low ceiling, a car lift and a tall opening create different fit questions. A conversion needs its own equipment and site assessment.

Ask HUSH to confirm whether your proposed conversion is within its available service scope before arranging that work.

Check the full path of the moving door and its equipment, not just the space at the front wall. Clopay’s track guide explains how the available space affects track selection. The required clearance must come from the drawings for the system being quoted.

Rough opening vs finished door size

The rough opening is the unfinished framing. The finished opening is the space after the specified jamb and finish details are in place. Ordering dimensions depend on the mounting arrangement, so a blanket rule about adding or subtracting a few inches can give the wrong result.

Clopay’s opening guidance distinguishes typical residential mounting from other jamb arrangements. Keep rough-opening and finished-opening measurements labelled separately. Let the installer confirm the selected model’s drawing before any framing change or door order.

When do you need a custom-size garage door?

A custom size is needed when the measured opening does not match a size offered for the chosen model. Confirm available size increments, track options and site requirements before ordering. An opening may need separate work even when a custom door is available.

Custom does not mean every dimension is available in every model. Clopay lists model-dependent custom increments, while Garaga publishes its own size range. Confirm the specific door, mounting details and expected lead time on the quote. Capping, trim changes or structural alterations need their own agreed scope.