Bathroom Mirror Size: Chart and Calculator by Vanity Width

Measure the vanity, not the sink, and subtract. That one habit fixes most of the bathroom mirror mistakes I see: the tiny mirror floating over a long counter, or the oversized one crashing into the sconces. Once you have the width, choosing a frame, a shape or one of the lighted LED bathroom mirrors gets much easier.

Below you will find the calculator, the full chart for every common vanity width (single and double), and what to do when your bathroom does not fit the rule.

Calculator

What size mirror for your vanity?

Mirror width30 in28 to 32 in works

Mirror height40 inputs the centre near eye level

Bottom edge40 infrom the floor, 6 in above the counter

Rule used: leave 2 to 4 inches of wall on each side of the mirror (ideal 3), bottom edge about 6 inches above the counter, centre near 60 inches. Designer guidelines, not building code. For an accessible bathroom, the 2010 ADA Standards put the bottom of the reflecting surface at 40 inches maximum.

The Rule: 2 to 4 Inches of Wall on Each Side

There is no building code for bathroom mirror width. What exists is a design guideline that kitchen and bath designers, mirror makers and vanity brands repeat in slightly different words: keep the mirror a little narrower than the vanity so the cabinet frames it. I use the version that is easiest to measure:

Minimum: vanity width minus 8 inches (4 inches of wall showing on each side).
Maximum: vanity width minus 4 inches (2 inches on each side).
Ideal: vanity width minus 6 inches (3 inches on each side).

Why narrower? The vanity is the visual base, and a mirror that sits inside its edges looks planted on it. Those few inches also leave room for sconces, a towel ring or the door casing, and they hide the small errors that happen when the vanity is not perfectly centered on the wall.

Measure the full cabinet or countertop, edge to edge, including any overhang of the top. If the counter is wider than the cabinet below it, use the counter: that is the line your eye reads.

Mirror width by vanity width. Leave 2 to 4 inches of wall on each side (ideal 3). A design guideline, not a building code.

Bathroom Mirror Size Chart by Vanity Width

These are the numbers the calculator above uses. Widths are in inches. If you cannot find a mirror at the ideal width, anything inside the range looks right.

Vanity width	Mirror width range	Ideal mirror width	Wall showing each side
24 in	16 to 20 in	18 in	2 to 4 in
30 in	22 to 26 in	24 in	2 to 4 in
36 in	28 to 32 in	30 in	2 to 4 in
42 in	34 to 38 in	36 in	2 to 4 in
48 in	40 to 44 in	42 in	2 to 4 in
60 in	52 to 56 in	54 in	2 to 4 in
72 in	64 to 68 in	66 in	2 to 4 in

Double vanities: one mirror or two

For two sinks you can run one long mirror using the chart above, or hang two mirrors. With two, split the vanity into two equal halves and apply the same rule to each half, centering each mirror over its sink.

Double vanity width	Each mirror (range)	Each mirror (ideal)	Gap between the two mirrors
48 in	16 to 20 in	18 in	4 to 8 in
60 in	22 to 26 in	24 in	4 to 8 in
72 in	28 to 32 in	30 in	4 to 8 in

The gap in the middle is simply the two inner margins added together. If your sinks are not centered in each half (it happens with some double vanities), center each mirror on its faucet instead and keep at least 4 inches between the mirrors.

What Size Mirror for a 36 Inch Vanity?

A mirror 28 to 32 inches wide, and 30 inches is the one I would buy. The 36 inch vanity is the most common single size in American bathrooms, so you will find plenty of 30 inch mirrors in rectangular, round and arched shapes. For height, 30 to 36 inches tall suits most 8 foot ceilings; a 30 by 36 inch rectangle hung vertically is a very safe choice.

A round mirror is the exception to the width rule. A circle looks smaller than a rectangle of the same width, so over a 36 inch vanity I go to the top of the range: a 30 to 32 inch round.

What Size Mirror for a 48 Inch Vanity?

Go 40 to 44 inches wide, ideally 42. At this width a horizontal rectangle (wider than tall) usually looks better than a vertical one, for example something around 40 by 30 inches. If you plan sconces on both sides, measure for them before you choose: two sconces plus a 42 inch mirror need about 54 inches of wall, so on a 48 inch vanity the lights will sit slightly outside the cabinet, which is normal and looks fine.

What Size Mirror for a 60 Inch Vanity?

For one sink, a single mirror 52 to 56 inches wide (54 ideal). For two sinks, two mirrors 22 to 26 inches wide (24 ideal), each centered on a faucet. One long mirror makes a small bathroom feel bigger and is easier to clean; two mirrors give each person their own zone and leave room for a light between them.

What Size Mirror for a 24, 30, 42 or 72 Inch Vanity?

24 in: 16 to 20 inches wide, ideally 18. In a powder room a 20 inch round or oval is lovely.
30 in: 22 to 26 inches wide, ideally 24. Stock 24 by 30 and 24 by 36 inch mirrors fit perfectly.
42 in: 34 to 38 inches wide, ideally 36.
72 in: one mirror 64 to 68 inches wide (66 ideal), or two mirrors 28 to 32 inches wide (30 ideal).

How Tall Should a Bathroom Mirror Be?

Width follows the vanity; height follows the wall and the people using it. Most bathroom mirrors that look right are 30 to 40 inches tall. The practical checks:

Bottom edge: it should clear the faucet and the backsplash, usually 5 to 10 inches above the countertop.
Top edge: a few inches above the head of the tallest person who uses it, so nobody sees their forehead cut off.
Lights above: leave at least a few inches between the top of the mirror and a fixture mounted over it.

I go through all the measurements, including what changes for tall and short households and medicine cabinets, in the bathroom mirror height guide.

Can a Mirror Be Wider Than the Vanity?

Yes, with intent. A mirror wider than the vanity works in three situations:

Wall to wall in an alcove. When the vanity fills a niche, a mirror that runs the full width of the niche (and often up to the ceiling) reads as architecture, not as a mistake.
Small, windowless bathrooms. A very large mirror reflects more light and makes the room look deeper. Here a mirror a few inches past the vanity edges can be the right call.
Very short vanities. A wall-hung sink or a 20 inch cabinet can carry a mirror slightly wider than itself, especially a round one.

What does not work is a mirror that is only a little wider, an inch or two past each edge. It looks like a measuring error. If you go wider, go clearly wider, or go wall to wall.

Can a Bathroom Mirror Be Wider Than the Sink?

Almost always it should be. People sometimes confuse the sink with the vanity: a basin is usually 16 to 22 inches across, while the vanity around it is much wider. Size the mirror from the vanity using the chart, and it will naturally be wider than the sink. The only time I size from the sink is on a pedestal sink or a wall-hung basin with no cabinet, where the mirror is typically about as wide as the basin, or a little wider.

Shape Changes the Size You Need

Rectangular mirrors

The chart applies as written. Hang vertical (portrait) on vanities up to about 36 inches and horizontal (landscape) on wider ones, unless the ceiling is high.

Round mirrors

Use the top of the range. A round mirror has less glass at the corners, so it reads smaller; on a 30 inch vanity I would choose a 24 to 26 inch round rather than a 22.

Oval and arched mirrors

Use the ideal width and let the height do the work. A tall arch over a 30 inch vanity can be 36 inches tall or more, which suits rooms with 9 foot ceilings.

Medicine cabinets

Medicine cabinets come in fewer sizes, so pick the closest one inside the range. Recessed cabinets also have to fit between wall studs, which are usually 16 inches apart on center in American homes; check before you choose a wide recessed model. My guide to how to measure for a medicine cabinet walks through it.

Don't Forget What Hangs Next to the Mirror

Sconces, towel bars and the edge of the shower all compete for the same strip of wall. Wall sconces usually need around 4 to 6 inches of space at their widest point, so if lights go on both sides, add their widths to the mirror width and check the total against the wall, not just the vanity.

Heavier glass mirrors over 30 inches wide deserve proper hardware. If yours is a big framed piece, read how to hang a heavy mirror before you drill; a French cleat makes centering much easier. And if you have not chosen the mirror yet, my picks of framed and frameless bathroom wall mirrors list the sizes each one comes in.

Sources

U.S. DOE Building America Solution Center: Advanced framing, minimum wall studs Wall studs traditionally spaced 16 inches on center, which limits recessed medicine cabinets.
NKBA: Bathroom Planning Guidelines with Access Standards Vanity task lighting beside the mirror at eye level, the reason to leave wall for sconces.

What is the standard size of a bathroom mirror?

There is no single standard, but the most common stock sizes are 24 by 30, 24 by 36, 30 by 36 and 36 by 48 inches, because they match the most common vanities (30, 36 and 48 inches). The right size for your bathroom is the one that leaves 2 to 4 inches of wall on each side of the vanity, which for a 36 inch vanity means a mirror 28 to 32 inches wide.

Is a 24 inch mirror too small for a 36 inch vanity?

It is on the small side. A 24 inch mirror leaves 6 inches of wall on each side of a 36 inch vanity, so it tends to look like it is floating. The guideline I use puts the mirror at 28 to 32 inches wide for that vanity. A 24 inch mirror can still work if you add a sconce on each side, because the lights fill the extra wall and make the group look intentional.

Should a bathroom mirror be bigger or smaller than the vanity?

Smaller, in most bathrooms. A mirror 4 to 8 inches narrower than the vanity lets the cabinet frame it and leaves room for lights and towel hooks. A mirror bigger than the vanity works only when it is clearly bigger, such as a wall-to-wall mirror in an alcove or a large mirror in a small windowless room. A mirror just an inch or two wider looks like a mistake.

What size bathroom mirror should I use with a 30-inch vanity?

A mirror 22 to 26 inches wide, ideally 24 inches. That leaves 2 to 4 inches of wall on each side of the vanity. Stock 24 by 30 and 24 by 36 inch rectangles fit a 30 inch vanity well. If you prefer a round mirror, choose the top of the range, around 24 to 26 inches, because a circle looks smaller than a rectangle of the same width.

What size mirror is best for a 42-inch vanity?

A mirror 34 to 38 inches wide, and 36 inches is the ideal. It leaves about 3 inches of wall on each side. At this width a horizontal rectangle often looks better than a tall vertical one, unless your ceiling is higher than 8 feet. If sconces go on both sides, check that the mirror plus both lights still fit the wall comfortably.

What size mirror for a 48 inch vanity with 2 sconces?

Stay at the low end of the range, around 40 inches wide. A 48 inch vanity normally takes a 40 to 44 inch mirror, but two sconces each need some wall space plus a little breathing room from the mirror edge. With a 40 inch mirror the lights sit near the vanity edges, which looks balanced. Measure the sconce backplates before you buy the mirror.

Keep reading: How high to hang a bathroom mirror · Best LED bathroom mirrors · Best bathroom wall mirrors · How to hang a heavy mirror