Bathroom Mirror Size Calculator

Choose a vanity mirror size that fits the cabinet, faucet, and wall height instead of guessing from the box label. The calculator uses vanity width, vanity height, faucet height above the counter, and ceiling height to suggest a practical width range, mirror height, and bottom-edge placement.

How to use this calculator

Enter the vanity width and height in inches, then add the faucet height measured above the counter and the ceiling height. The result shows a suggested mirror width range, a suggested height, and the bottom edge height above the floor. If you are also planning the room layout, the square footage calculator can help measure available wall and floor area.

How it works

The width range follows the calculator rule of 70 percent of vanity width up to vanity width minus 4 inches. Bottom placement is:

$bottom\ edge = vanity\ height + faucet\ height + 4$

For a 36 inch vanity, 34 inch vanity height, 8 inch faucet height, and 96 inch ceiling, the mirror width is about 25.2 to 32 inches. The bottom edge is about 46 inches above the floor, and suggested height is about 27 inches.

Sizing tips

For double vanities, calculate each mirror from the sink section rather than the full cabinet if you are using two separate mirrors. Leave room for sconces, medicine cabinets, trim, and tile edges. If a mirror sits over a tiled backsplash, compare the mirror plan with the tile calculator before ordering materials.