How to measure your windows.
One compact reference with the visual guide, six-step checklist, and mount rules in the same place.
Inside Mount
Order the exact measured opening. Factory deductions are applied automatically.
Minimum depth: ½" for standard blinds, 1¾" for larger headrails.
Outside Mount
Add 2–3" to width and height beyond the frame for better light coverage.
Mount roughly 2" above the frame for a taller visual line.
Visual Reference
The original measuring sheet.
Step 1
Use a steel tape measure
Cloth or plastic tapes stretch. Use metal only.
Step 2
Write width first
Always record dimensions in W × H order.
Step 3
Measure width three times
Top, middle, bottom. Record all three numbers.
Step 4
Measure height three times
Left, center, right. Use the tallest for inside mount.
Step 5
Round to the nearest ⅛ inch
That is the cleanest ordering format for production.
Step 6
Choose mount style
Inside and outside mount follow different deduction rules.