Standard window and blind sizes
Window size codes decoded, common sizes by window type, and why a "standard" size is only a starting point.
Short answer: window makers use four-digit size codes: the first two digits are the width in feet and inches, the last two the height. A 2438 window is 2 ft 4 in by 3 ft 8 in, or 28 × 44 in.[1 · Oct 29, 2026] But the code may describe the rough opening in the wall rather than the glass you'll fit a blind into, so measure before you order.[1 · Oct 29, 2026]
Common window sizes by type
| Window type | Common sizes (code: width × height) |
|---|---|
| Picture | 3020: 36 × 24 in (91.4 × 61.0 cm) 5030: 60 × 36 in (152.4 × 91.4 cm) 6040: 72 × 48 in (182.9 × 121.9 cm) 4050: 48 × 60 in (121.9 × 152.4 cm) |
| Double-hung | 2030: 24 × 36 in (61.0 × 91.4 cm) 2044: 24 × 52 in (61.0 × 132.1 cm) 2840: 32 × 48 in (81.3 × 121.9 cm) 2852: 32 × 62 in (81.3 × 157.5 cm) |
| Casement | 2436: 28 × 42 in (71.1 × 106.7 cm) 2640: 30 × 48 in (76.2 × 121.9 cm) 2850: 32 × 60 in (81.3 × 152.4 cm) 3060: 36 × 72 in (91.4 × 182.9 cm) |
| Awning | 3020: 36 × 24 in (91.4 × 61.0 cm) 4024: 48 × 28 in (121.9 × 71.1 cm) 5030: 60 × 36 in (152.4 × 91.4 cm) |
| Sliding | 3020: 36 × 24 in (91.4 × 61.0 cm) 3030: 36 × 36 in (91.4 × 91.4 cm) 5030: 60 × 36 in (152.4 × 91.4 cm) 6040: 72 × 48 in (182.9 × 121.9 cm) |
Size codes from Pella's standard window sizes guide.[1 · Oct 29, 2026] We decoded each code into inches and converted to centimeters at exactly 2.54 cm per inch.[2 · Oct 29, 2026] Pella notes that a standard size isn't necessarily one that's in stock.[1 · Oct 29, 2026]
Why the code isn't your blind size. A blind for an inside mount is sized to the inside of the finished frame, measured at three points.[3 · Oct 29, 2026] That's smaller than the rough opening and can differ from window to window, so treat the chart as a guide to what's common, not as an order size.
Ready-made blind sizes
Stores group ready-made blinds by window width; Home Depot's filters run from under 20 in to over 60 in.[4 · Oct 29, 2026] Some of its ready-made faux wood blinds are sold to be cut down to your width.[4 · Oct 29, 2026] A complete list of stock widths that every store carries: Unverified. We couldn't confirm a reliable source for this yet.
- For an inside mount, a stock blind needs to be no wider than your narrowest reading, so you'll usually have it cut. Home Depot cuts blinds bought in its stores for free.[4 · Oct 29, 2026]
- For an outside mount, choose a stock width that covers the opening plus overlap. See what size do I need.
Bay windows
In many bay windows the center window is about half the total width and each side about a quarter, angled out at 30 or 45 degrees.[1 · Oct 29, 2026] Each window still gets its own measurement: see bay window blinds.
Affiliate links: if you buy through a link in this box we may earn a commission, at no extra cost to you. It does not change the sizes or sources on this page. How we handle affiliate links.
Sources: 1. Pella, Standard window sizes. 2. NIST, SI units: length. 3. Levolor, How to measure windows for blinds and shades. 4. The Home Depot, Blinds category and buying notes. Checked Oct 29, 2026. Trademarks belong to their owners; figures are restated in our own words and tables, not reproduced.