Blind Size Calculator
Measure your window at three width points and three height points, then choose inside mount or outside mount for the final blind size.
Omni's guide says to use the smallest width and tallest height for inside mount blinds, then add overlap for outside mount blinds.
Recommended Blind Size
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Run the calculation to see the recommended blind size.
Quick Answer
For inside mount blinds, use the smallest measured width and the tallest measured height. For outside mount blinds, use the widest width and add overlap.
How to Calculate Blind Size
- Measure the top, middle, and bottom widths.
- Measure the left, center, and right heights.
- Choose your mount type.
- Click Calculate to get the blind size recommendation.
Formula
Inside mount width = smallest width
Inside mount height = tallest height
Outside mount width = widest width + overlap
Outside mount height = tallest height + overlap
Worked Examples
Example 1: 36 / 35.5 / 36.25 inch widths and 60 / 60.5 / 59.75 inch heights give a 35.5 x 60.5 inch inside mount size.
Example 2: The same measurements become a slightly larger outside mount once you add overlap.
Example 3: If the window is uneven, outside mount is often the safer choice.
How to Interpret the Result
| Mount type | Interpretation |
|---|---|
| Inside mount | Fits within the window frame for a clean built-in look. |
| Outside mount | Covers more of the wall and can block more light. |
| Uneven window | If measurements differ a lot, outside mount may be more forgiving. |
Frequently Asked Questions
Related Calculators
References
- OmniCalculator reference page
- The reference page recommends the smallest width and tallest height for inside mount blinds.
- Last reviewed: March 2026.