How to Measure for Roll-Up Shutters: A Step-by-Step Guide for Canadian Homes

The short answer

Measure the clear opening’s width and height in three places and write down the largest number for each. Then check that there is enough flat wall around the opening for the guide rails and the box: about 4½” of extra width and 10½” above a typical window, and more for patios, cabanas and garage doors.

By the Roll Pro production team: 30+ years manufacturing roll shutters and roll-up doors in Concord, Ontario. Updated October 2026

Every roll-up shutter is built to order, so your measurements are the starting point for every part we cut. Getting them right takes about 15 minutes per opening, a tape measure and a level. Below we walk through each step, including how much wall space each type of opening needs.

The method works for window shutters, door and patio shutters, cabana and service-counter shutters, sheds, laneways and roll-up garage doors. If your opening doesn’t fit the rules below, call us before you order. It is much easier to fix a number on paper than a shutter on the wall.

Before you measure: tools and one quick check

You need only a few things:

• A steel tape measure (a laser measure helps on wide garage openings)
• A level, ideally 4 ft long
• A pencil and paper, or the notes app on your phone
• A helper for any opening wider than about 8 ft
• Your phone camera, for photos of the opening and the wall around it

Write every number in inches, to the nearest ⅛ inch, and always list width first, then height.

Next, look at how the shutter will sit on your wall. A typical roll-up shutter mounts on the face of the wall: the box sits above the opening and a guide rail runs down each side. That keeps the whole opening clear when the shutter is rolled up. It also means you need flat wall space around the opening, not just the opening itself. If your opening is deeply recessed, sits right against a corner or has no room above it, talk to us first, because it may need a different mounting.

How to measure for a roll-up shutter in 6 steps

Step 1: Measure the clear opening width

The clear width is the distance between the left and right edges of the opening you want covered. On a window, that is usually the brick or siding opening, not the glass or the window frame.

Measure across the top, the middle and the bottom. Write down the largest of the three. The guide rails sit just outside the opening, so using the largest number keeps them from cutting into the opening at its widest point.

Step 2: Measure the clear opening height

The clear height runs from the top of the opening (the underside of the header or lintel) down to the surface the shutter will close onto. That can be a window sill, a counter, a deck or a floor.

Measure on the left, in the centre and on the right. Again, write down the largest number.

Step 3: Check the wall space for the box and guide rails

The box and guide rails need flat wall around the opening. Add these allowances to your clear opening to see how much wall space the finished shutter will cover:

For example, a 60″ × 48″ window needs a flat area of about 64½” × 58½”. A 72″ × 40″ cabana counter needs about 78″ × 52½”. The exact size depends on the shutter you choose, so treat these figures as minimums to check, not as cut sizes.

Take the clear width and height from inside the opening; the roll box and guide rails need the extra wall shown around it.

Step 4: Check the sill and the corners

Set your level on the sill or floor. The shutter’s bottom bar is straight, so a sloped sill leaves a gap at one end. If the bubble is off, measure the height at both ends and send us both numbers.

Then measure the two diagonals, corner to corner. If they differ noticeably, the opening is out of square. Send both diagonals and a photo so we can account for it.

Step 5: Look for anything in the way

Scan the wall space from Step 3 for obstructions: outdoor lights, cameras, hose bibs, downspouts, vents, gas meters, door handles and window sills that stick out. Above the opening, check for soffits, eavestroughs and low porch ceilings that could block the box.

The guide rails also need a solid surface to screw into. Brick, block, concrete and solid wood are ideal. On vinyl or aluminum siding, make sure there is solid backing behind where each rail will go.

Step 6: Choose the operator side and plan for power

Decide how you will open the shutter. Roll Pro offers four manual operators plus electric motors:

• Tape coiler: small and medium windows and counters
• Tape winch: larger windows, patio and shed doors
• Spring push-up: larger counters, sheds and storage
• Removable hand crank: openings where the box is hard to reach
• Electric motor: wall switch or remote control

Note which side you want the strap, crank or motor on, as seen from where you will operate it.

For a motorized shutter, note where the nearest outlet is, or where wiring can come out next to the box. A short note now saves an electrician’s second visit later.

7 measuring mistakes that delay an order

1. Measuring the glass or window frame instead of the full opening you want covered.
2. Rounding down, or keeping the smallest number. Record to the nearest ⅛” and keep the largest of your three readings.
3. Forgetting the space above the opening. A soffit, eavestrough or porch ceiling can leave no room for the box.
4. Swapping width and height. Always write width × height, in that order.
5. Measuring only once. Three readings per side catch walls that bow or taper.
6. Ignoring a sloped sill or deck. It leaves a gap under the bottom bar at one end.
7. Leaving out the operator side. A crank or motor on the wrong side can end up behind a downspout or a door.

Garage doors and laneways: a few extra rules

A roll-up garage door follows the same steps, with three differences.

• It needs the most wall space: about 7½” of extra width and about 15″ above the opening for the box. Measure the headroom between the top of the opening and the ceiling or any beam, and the side room on each side.
• It is motor-operated only. There is no manual version of our garage doors, so plan for power near the box.
• Safety devices are required. Every garage door needs infrared photo-eyes and an auto-reverse mechanism, in line with the UL 325 safety standard.

Still deciding on the door style itself? Our comparison of roll-up and sectional garage doors compares space, insulation, winter performance and security.

Frequently asked questions

Do I measure inside or outside the window frame?

Measure the full opening you want covered, usually edge to edge of the brick or siding opening. Don’t measure the glass or the window frame. The guide rails and box then mount on the wall just outside that opening.

How much space does a roll-up shutter need above a window?

About 10½” above windows and doors up to 96″ wide. Wider openings, patios and cabanas need about 12½”, and garage and laneway doors need about 15″. The exact box size depends on the height of the opening and the slat you choose.

How much room do the guide rails need on each side?

Roughly half of the extra width from the table above on each side. That is about 2¼” per side on a typical window and about 3¾” per side on a garage door.

Should I round my measurements up or down?

Neither. Record each reading to the nearest ⅛” and use the largest of your three readings for both width and height.

What if my opening isn’t square or level?

Measure both diagonals and the height at each end, then send us all four numbers with a photo. Uneven openings are common, especially on older homes and decks, and we can account for them before production.

Can I order a roll-up shutter online and install it myself?

Yes. Enter your sizes in our DIY shutter configurator, and follow our installation manuals for each operator type. We ship across Canada, and you can also pick up your order free at our Concord, Ontario facility.

How long does a custom roll-up shutter take?

Production takes 3 to 4 weeks after payment, plus delivery time. Roll Pro crews install in and around Toronto; outside that area, shutters are shipped for DIY or local installation.

Got your numbers? Here’s what to do next

Roll Pro is a Canadian manufacturer of aluminum roll shutters and roll-up doors in Concord, Ontario, shipping custom shutters across Canada. Every shutter is made to your exact opening and backed by up to a 7-year warranty, with a 4.7-star rating on Google reviews.

• Build it yourself: enter your sizes in the DIY shutter configurator.
• Get a free quote: send your width, height and photos through our quote form. Quotes are free and valid for 30 days.
• Talk to us: call (905) 532-0017 or toll-free 1 (855) 474-7657, or email sales@rollpro.ca.

Not sure which shutter fits your project? Browse our window shutters, cabana shutters, patio roll-up doors and roll-up garage doors.