Bathroom Mirror Size Calculator

in
Width of the vanity cabinet or countertop.
in
Floor-to-ceiling height.
in
Height of vanity top from the floor.
in
Gap between mirror top and ceiling.
Everyday Life

Find the ideal bathroom mirror width and height based on vanity width and ceiling height.

Formula

Width ≈ 75% of vanity width; Height = ceiling − clearance − vanity top − 8 in
  • Mirror width is typically 70–80% of vanity width.
  • An 8-inch gap above the vanity top is standard.
  • Adjust top clearance based on light fixture position.

36-inch vanity, 8-ft ceiling

Inputs
  • Vanity Width: 36 in
  • Ceiling Height: 96 in
  • Vanity Top Height: 36 in
  • Top Clearance: 6 in

Mirror width = 36×0.75 = 27 in. Mirror height = 96−6−36−8 = 46 in.

Frequently asked questions

How wide should my bathroom mirror be?
Typically 70–80% of vanity width, centered over the sink.
Should the mirror match the vanity width exactly?
It can, but leaving a few inches on each side is more visually balanced.
What about framed mirrors?
Account for frame width — measure the glass area, not the overall frame.
Can I use a full-wall mirror?
Yes — this calculator gives a standard recommendation, but design preferences vary.