Standard Window Sizes in Canada: The Complete Guide
Typical sizes for every window style (casement, hung, slider, awning, picture, bay, and basement), plus how to measure your openings and when a custom-made window is the smarter choice.
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How Window Sizing Works in Canada
Window sizes in Canada are listed width first, then height, in inches. A "2846" window is 2'8″ wide by 4'6″ tall. Two numbers matter when you're replacing:
- Rough opening: the framed hole in the wall.
- Window (unit) size: the actual frame dimensions, typically about ½″ smaller than the rough opening on each dimension to leave room for shimming, levelling, and insulation.
"Standard" sizes are really just the most common manufacturing increments. Unlike door sizes, which follow tighter conventions, window openings vary enormously between decades of Toronto housing stock, which is why most quality replacements are custom-built to the opening.
Standard Window Sizes by Style
Casement Windows (crank-out)
| Dimension | Typical range | Most common |
|---|---|---|
| Width | 14″ – 36″ | 24″ – 30″ |
| Height | 24″ – 72″ | 36″ – 60″ |
Casements are Canada's most popular operating window; tall and narrow suits them. See our casement windows page for configurations.
Single & Double Hung Windows
| Dimension | Typical range | Most common |
|---|---|---|
| Width | 24″ – 48″ | 28″ – 36″ |
| Height | 36″ – 72″ | 44″ – 60″ |
Slider Windows
| Dimension | Typical range | Most common |
|---|---|---|
| Width | 36″ – 84″ | 48″ – 72″ |
| Height | 24″ – 60″ | 24″ – 36″ |
Awning Windows (crank-open from bottom)
| Dimension | Typical range |
|---|---|
| Width | 24″ – 46″ |
| Height | 20″ – 42″ |
Picture (Fixed) Windows
| Dimension | Typical range |
|---|---|
| Width | 24″ – 96″ |
| Height | 12″ – 96″ |
Fixed glass can go bigger than any operating style, because size limits come from glass thickness and handling rather than hardware.
Bay & Bow Windows
| Dimension | Bay (3 panels) | Bow (4–6 panels) |
|---|---|---|
| Width | 42″ – 126″ | 60″ – 144″ |
| Height | 36″ – 78″ | 36″ – 78″ |
Choosing between them? See bay vs. bow windows.
Basement Windows (hopper & slider)
| Dimension | Typical range |
|---|---|
| Width | 30″ – 42″ |
| Height | 12″ – 24″ |
Replacing them? Our basement window replacement service covers styles and Toronto pricing.
Common Window Sizes by Room
| Room | Typical styles | Common sizes (W × H) |
|---|---|---|
| Living room | Picture, bay/bow, casement combos | 48″×60″ to 96″×62″ |
| Bedroom | Casement, hung, slider | 24″×36″ to 48″×60″ (see egress note below) |
| Kitchen | Casement, slider, awning over sink | 36″×36″ to 60″×48″ |
| Bathroom | Awning, hopper, small slider | 24″×24″ to 36″×36″ |
| Basement | Hopper, slider | 30″×12″ to 42″×24″ |
Bedroom Windows: The Egress Minimum
How to Measure a Window Opening
- Width: measure jamb-to-jamb at the top, middle, and bottom. Record the smallest of the three.
- Height: measure sill to head jamb at the left, centre, and right. Again, keep the smallest.
- Depth: measure the frame depth; older Toronto brick homes often have deeper openings that affect frame selection.
- Check square: measure both diagonals; a difference over ¼″ means the opening is out of square, which is common in older homes and settling foundations, and one more reason replacements are best custom-made.
Measuring for a quote is useful, but don't order off your own numbers. Every Optima installation starts with a professional measure, and the units are then built to the exact opening.
Standard vs. Custom: What GTA Homes Actually Need
Stock-size windows suit new construction, where framers build openings to catalogue dimensions. Replacement is the opposite problem: the opening already exists, cut into brick or framed decades ago to whatever was standard then. Forcing a stock window into a non-stock opening means shims, filler strips, and compromised insulation.
That's why Optima custom-manufactures every replacement window to the millimetre in our Etobicoke facility, so custom sizing is built into how we work, not an upcharge lottery. If you're comparing quotes, our cost calculator gives a fast ballpark by style and size.
Window Size FAQ
What is the most common window size in Canada?
How do I read a window size like "2846"?
What size does a bedroom window legally need to be in Ontario?
Is the rough opening the same as the window size?
Do custom-size windows cost more?
What size are standard basement windows?
Related Reading
Skip the Size Guesswork
Every Optima window is manufactured in Etobicoke to your exact opening, measured by us, guaranteed to fit.
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