How to use the vanity mirror size calculator
Pick Single sink or Double sink at the top. For a double vanity you can then choose two mirrors, one over each sink, or one long mirror.
Enter the vanity width and choose how the mirror is lit: a light fixture above it, or sconces on each side. Then add the ceiling height, the counter height, the backsplash height and the faucet height, measured from the countertop to the top of the faucet. Type measurements the way you would write them (36” or 3’) or tap the minus and plus buttons. The unit toggle switches to centimeters.
The calculator answers right away. The first panel gives the mirror size to buy, width by height, and the range of widths that suit the vanity. Tap through the stock widths below it. Each one turns green when it fits, amber when it is too narrow and red when it is too wide. The one marked “Best” sits closest to the middle of the range.
The second panel tells you where to hang it: the bottom edge, the top edge and the center height, plus the width and height of the light above or where the sconces go. The drawing shows the whole vanity wall to scale with a person for reference. Save it as an image to send to whoever is hanging it.
The rules behind the size and height
A few inches narrower than the vanity. The most repeated vanity mirror rule is that the mirror should never be wider than the vanity, and should look a little narrower. The calculator keeps at least an inch of vanity showing on each side, and keeps the mirror at least 70% as wide as the vanity (no more than 12 inches narrower on a very wide one) so it doesn’t look skimpy.
Two mirrors, one per sink. Over a double vanity, each mirror is centered on its sink and sized to its half of the vanity, with a few inches of wall between them. With sconces, that gap widens to fit a shared sconce in the middle.
Clear the faucet and backsplash. The bottom edge sits at least 2 inches above whichever is taller, the faucet or the backsplash. Water splashes and a faucet that pokes into the mirror both look wrong. That usually puts the bottom 5 to 10 inches above the counter.
Center near eye level. A vanity mirror works best with its center around 60 to 66 inches from the floor, where most adults look. The calculator picks the tallest stock height that fits without pushing the center above 66 inches, and lifts a short mirror toward eye level if there is room.
Room for the light above. A vanity light is usually centered about 75 to 80 inches from the floor, or 8 inches under a low ceiling, and the mirror stops a few inches below it. The light itself should be about three-quarters of the mirror’s width and never wider.
Sconces at eye level, 28 to 40 inches apart. Sconces on each side light the face evenly with no shadows under the eyes. Mount them 60 to 66 inches high and 28 to 40 inches apart. With a few inches between each sconce and the mirror, that keeps the mirror to about 29 inches wide.
Assumptions
The vanity is drawn with standard doors and a 4 inch toe kick. Faucets are taken as deck-mounted at the center of each sink. If yours is wall-mounted above the sink, enter its top as the faucet height. Sinks on a double vanity are centered a quarter of the way in from each end.
Light bars are assumed about 6 inches tall and sconces about 12 inches tall and 5 inches wide. Real fixtures vary, so check the box for the one you like. Medicine cabinets follow the same width rules, but check the recess depth and the stud spacing before you buy.
The calculator works with a flat wall and a level counter. For a mirror that runs the full width of the vanity, or a wall of mirror up to the ceiling, the width rule doesn’t apply. That is a deliberate design choice and needs the lights mounted on the glass.
Worked example
Say the vanity is 36 inches wide with one sink, a 34 inch counter, a 4 inch backsplash, an 8 inch faucet, an 8 foot ceiling and a light above.
- Width: 70% of 36 inches is about 25 inches, and 2 inches narrower is 34 inches. The calculator suggests a 30 inch mirror.
- Height: the bottom edge has to clear the 8 inch faucet by 2 inches, so it can’t go lower than 44 inches. The light centers at 80 inches, so the mirror has to stop by 74 inches. That leaves room for a 30 inch tall mirror.
- Placement: hang it from 44 to 74 inches. Its center lands at 59 inches, just under eye level. The light above should be about 23 inches wide.
Switch to sconces and the mirror can go taller, since it no longer has to stop under a light. A 40 inch tall mirror fits, with its center at 64 inches. The width drops to 28 inches so the sconces, centered 64 inches high, stay 39 inches apart.
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Vanity Mirror Size Calculator FAQ
What size mirror goes over a 36 inch vanity?
A mirror between about 25 and 34 inches wide, so a 30 inch mirror is the usual choice. It should be a few inches narrower than the vanity, never wider. With an 8 foot ceiling and a light above, a 30 inch tall mirror fits between the faucet and the light.
Should a bathroom mirror be the same width as the vanity?
No. Keep the mirror a few inches narrower than the vanity, at least an inch in from each side. A mirror as wide as or wider than the vanity looks top-heavy and crowds the light fixtures. Aim for about 70% of the vanity width up to 2 inches narrower.
How high should a vanity mirror be hung?
Hang it so the bottom edge clears the faucet and the backsplash by a couple of inches, usually 5 to 10 inches above the counter. Then check that the center lands near eye level, about 60 to 66 inches from the floor. With a standard 34 inch counter, the bottom edge often ends up around 44 inches.
One mirror or two over a double vanity?
Two mirrors, each centered over a sink, give each person their own space and leave room for a sconce between them. One long mirror makes the vanity look wider and is easier to light with a single bar. Both work; the calculator sizes either one.
How far apart should vanity sconces be?
Mount sconces about 60 to 66 inches high, at eye level, and 28 to 40 inches apart so they light both sides of your face evenly. That limits the mirror between them to about 29 inches wide. For a wider mirror, mount the sconces on the mirror or add a light above.