Window Blinds Calculator
Calculate the correct blind size for your windows.
Get inside and outside mount measurements.
Recommended Blind Size
Window blind sizing depends on whether you mount inside or outside the window frame.
Inside mount (blinds fit inside the frame):
- Measure width at top, middle, and bottom — use the narrowest
- Measure height on left, center, and right — use the longest
- Deduct 1/4 inch (6 mm) from width for clearance
- Most manufacturers will make the deduction for you
Outside mount (blinds cover the frame):
- Add 1.5–3 inches (4–8 cm) to each side of the window
- Add 3 inches (8 cm) above the window
- Add 1 inch (2.5 cm) below the window sill
Minimum inside mount depth requirements:
| Blind Type | Min Depth Needed |
|---|---|
| Mini blinds | 1 inch (2.5 cm) |
| Faux wood blinds | 2 inches (5 cm) |
| Real wood blinds | 2.5 inches (6 cm) |
| Cellular shades | 1.5 inches (4 cm) |
| Roller shades | 1.5 inches (4 cm) |
Always measure in three places and use the most conservative measurement.