How to Measure an Angled Bay Window

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๐Ÿ“˜ Note:
If your bay window has walls, frames, or trim separating each section, you can treat them as individual windows and measure each one separately.
If the windows are connected with no separation between them, you should not measure them like standard windows. Otherwise, the valances may collide at the corners during installation.
Please follow the steps below to measure your bay window correctly.

Before you begin measuring your shades, first identify the valance depth of your selected product (A1). You can find this information in the reference table below.

Valance Depth Reference Table

Shades Type Valance Type Valance Depth(A1)
Roller shades
Zebra Shades
Shangri-La Shades
Cordless Roman Shades
Standard 2โ…"(67mm)
Cassette 3 7/16" (88mm)
White Square / Black Square 3โ…œ" (86mm)
Cellular shades
Plain Fold Roman Shades
Soft Fold Roman Shades
Standard 2 9/16" (65mm)
Dual shades Standard 4" (102mm)
Woven Wood Shades Standard / Fabric-Wrapped 3ยฝ" (89mm)

Next, check for any obstructions that extend beyond the window frameโ€”such as window handles or air vents. Measure how far these obstructions protrude past the frame (A2).

Then, calculate your final A Measurement:
A = A1 (Valance Depth) + A2 (Obstruction Projection)

Example:
If the valance depth is 3 inches and a window handle extends ยฝ inch beyond the frame, the combined measurement will be 3ยฝ inches. This will be your A Measurement.

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โœ… What Youโ€™ll Need:
Two pieces of A4 or A5 card
Pencil
Metal tape measure
Ruler

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Step 1

Place two straight-edged pieces of card side by side and mark A Measurement on the edge of each piece (valance depth + any obstructions).


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Step 2

Position the two marked cards on your bay windowsill and slide them toward each other until the A marks on both pieces line up perfectly.


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Step 3

Where the edge of each card meets the window frame, make a light pencil mark on the sill.
Repeat this process for every corner of your angled bay.

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Step 4

Once all marks are in place, measure the distance from one mark to the next.
This measurement will determine the exact width of each shade you need to order.

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๐Ÿ’ก Tip:
Please select Inside Mount when placing your order.
During production, the factory will apply an additional 3/16 inch (about 4.8 mm) to ensure a safe and proper installation.

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Step 5

To measure the shadeโ€™s height, measure from the top of the valance installation point straight down to your preferred stopping pointโ€”typically the windowsill.

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