Bathroom Mirror Size Calculator — Free Online Tool
A mirror wider than the vanity looks like a mistake; too narrow looks lost. This bathroom mirror size calculator applies the standard sizing rule to your vanity width.
What is the Bathroom Mirror Size Calculator?
The rule: the mirror should be about 4 inches narrower than the vanity overall — and never wider than the vanity itself. Around 30 inches of height suits standard 8-foot ceilings with the mirror starting a few inches above the backsplash. These proportions keep the mirror visually anchored to the vanity instead of floating.
Round or arched mirrors can break the width rule slightly since their visual weight is lighter. For double vanities, either one wide mirror or two matching mirrors centered over each sink both work. This bathroom mirror size calculator gives the classic single-mirror recommendation — adjust to taste from there.
How to use this calculator
- Measure your vanity width in inches.
- Enter it and click Calculate Mirror Size.
- Choose your shape — round and arched styles can run slightly narrower.
- Hang with the bottom edge 5–10" above the backsplash.
Formula
Frequently asked questions
Can a bathroom mirror be wider than the vanity?
No — it looks like a mistake. Keep it narrower; this bathroom mirror size calculator uses 4 inches narrower.
How high should I hang a bathroom mirror?
Bottom edge roughly 5–10 inches above the backsplash, centered at average eye level.
What about double vanities?
Either one wide mirror spanning both sinks or two matching mirrors, each centered over its sink.
Do round mirrors follow the same rule?
Roughly — but their lighter visual weight means you can go slightly narrower without it looking lost.