Bathroom Mirror Size Calculator
Choose a mirror type, enter your vanity and ceiling measurements, and get a practical size recommendation that matches the room.
The recommendations follow the Omni guidance: the mirror stays slightly narrower than the vanity and comfortably below the ceiling line.
Recommended Mirror Size
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Run the calculation to see the recommended size.
Quick Answer
For most bathrooms, the mirror should be a little narrower than the vanity and tall enough to leave usable space above and below the reflection area.
How to Use the Calculator
- Choose the mirror shape or layout.
- Enter vanity width and height.
- Enter the ceiling height.
- Click Calculate to see the recommended mirror dimensions.
Formula
Rectangular mirror width = vanity width - 4 inches
Double vanity mirror width = vanity width - 8 inches
Mirror height = ceiling height - (vanity height + 12 inches)
Circular mirror diameter = smaller of the width limit and height limit
Worked Examples
Example 1: A 36 inch vanity, 36 inch vanity height, and 96 inch ceiling suggest a 32 x 48 inch rectangular mirror.
Example 2: The same vanity works as a 28 x 48 inch double mirror setup.
Example 3: A circular mirror on the same vanity should stay near 32 inches in diameter, provided the ceiling clearance also allows it.
How to Interpret the Result
| Measurement | Meaning |
|---|---|
| Width | Should leave a few inches of negative space on each side of the vanity. |
| Height | Should stay comfortably below the ceiling and above the vanity top. |
| Shape | Rectangular is most common, while circular or double options suit other designs. |
Frequently Asked Questions
Related Calculators
References
- OmniCalculator reference page
- Clearance rules and width recommendations follow the Omni guidance for vanity mirrors.
- Last reviewed: March 2026.