The mirror is usually the last decision in a bathroom project, which is exactly why it so often goes wrong. By the time you get to it, the vanity is installed and the lighting is picked, and you end up choosing from whatever fits the leftover budget or looked good on a showroom wall with no vanity underneath it.
There is a reliable rule that handles the large majority of bathrooms, and a short list of clearances that handles the rest.
The rule: narrower than the vanity
A bathroom mirror should be a few inches narrower than the vanity below it, roughly 4 to 8 inches less than the total vanity width, leaving about 2 to 4 inches of wall visible on each side. In a standard bathroom the mirror should not be wider than the vanity. That reveal on either side is what makes the mirror read as intentional rather than crammed into place.
|
Vanity width |
Mirror width |
Notes |
|
24" |
20" – 22" |
Powder room; consider a round mirror |
|
30" |
24" – 26" |
Most common small-bath size |
|
36" |
30" – 32" |
Standard single vanity |
|
42" |
34" – 38" |
|
|
48" |
40" – 44" |
Single sink |
|
60" single sink |
52" – 56" |
Or a narrower mirror centered on the sink |
|
60" double sink |
Two at 24" – 28" |
One per sink |
|
72" double sink |
Two at 30" – 36" |
One per sink |
Height is set by clearances, not a formula
There is no single correct mirror height, because the vertical space you have is defined by what sits above and below it. Work from three clearances:
● Bottom edge: about 5 to 10 inches above the countertop, which usually puts it 4 to 6 inches above the faucet. Lower than that and the mirror collects water spots and looks crowded against the backsplash.
● Top edge: 2 to 3 inches below the light fixture above it. If you are using a light bar, the mirror stops where the fixture begins.
● Center: near eye level for the people using the bath. A center around 60 to 65 inches above the floor works for most households.
A taller mirror makes a small bathroom feel taller, so if you have the vertical room between the counter and the fixture, use it.
Mirror size and lighting are one decision, not two
This is the part most people separate, and it is why so many bathrooms end up with a mirror that fights the fixtures. Decide the lighting layout first, then size the mirror to match it.
Light bar above the mirror
A wider mirror works here, because the fixture sits above rather than beside it. The standard proportion is a light bar 75 to 80 percent of the mirror width. A 48-inch mirror takes a 36 to 38 inch bar. Go much wider and the fixture overhangs awkwardly; much narrower and the outer edges of the mirror sit underlit. Mount the fixture so its center is roughly 75 to 80 inches above the floor, about 3 inches above the top of the mirror.
Sconces beside the mirror
Side lighting is the most flattering option for grooming, because it lights your face from both sides instead of casting shadows down from above. It also constrains the mirror. Sconces want to be spaced roughly 36 to 40 inches apart, centered on the sink, with their centers 60 to 70 inches above the floor. That means the mirror has to be narrow enough to leave real wall on both sides. Size the mirror to the sink, not the vanity, and check the sconce backplate width before you commit.
Lighted LED mirrors
A mirror with integrated perimeter or backlighting removes the clearance problem entirely. You get even, shadow-free front lighting, you can run the mirror as wide as the sizing rule allows, and you free up the wall. You still want an ambient ceiling source in the room; a lighted mirror handles the vanity, not the whole bathroom.
Double vanities: one mirror or two?
Two mirrors is the safer default. Each sink gets its own mirror and its own light, the proportions are easy to get right, and the result reads as deliberate. Size each one to its sink rather than to half the total vanity width.
One large mirror spanning both sinks can look excellent, but it needs the right lighting to carry it: a long single light bar, a row of evenly spaced sconces, or sconces mounted directly on the mirror. What does not work is a single oversized mirror chosen because it filled the wall, paired with two small fixtures sized for individual mirrors. That is the most common and most expensive mistake in a double-vanity bath.
Shape, frame, and finish
A frameless mirror disappears into the wall, which suits small bathrooms and minimal schemes. A framed mirror becomes a design element and is the easier way to tie the vanity wall into the rest of the room. Round mirrors soften a boxy bathroom, but you lose usable reflective surface at the edges, so plan on a diameter around 60 to 75 percent of the vanity width rather than matching the rectangle you would otherwise have chosen.
On metal finishes, match the mirror frame to either your plumbing fixtures or your lighting. Trying to match both usually means one of them is slightly off, and a deliberate contrast reads better than a near miss.
Frequently asked questions
Should the mirror be exactly as wide as the vanity?
No. A mirror matching the vanity width edge to edge looks like it was installed by accident. Leave 2 to 4 inches of wall on each side.
Can a mirror ever be wider than the vanity?
It can work in a wide-wall or floating-vanity design where the mirror is clearly treated as an architectural element, typically wall to wall. It rarely works when the mirror is only slightly wider, which just looks like a sizing error.
What size mirror goes over a 48-inch vanity?
40 to 44 inches wide for a single sink. Pair it with a 36 to 38 inch light bar if you are lighting from above.
What if there is a window right next to the vanity?
Reduce the mirror width and center it on the sink rather than the vanity, and favor a single sconce or an above-mirror fixture over a pair. Never plan a sconce where it will collide with window trim.
What diameter round mirror suits a 36-inch vanity?
24 to 28 inches is the usual range. Check that the bottom of the circle still clears the faucet by several inches.
Shop mirrors and vanity lighting
Browse mirrors, bathroom and vanity lighting, and wall sconces. Every product page lists overall dimensions, so you can check them against the chart above before you order.
If you are working through a bathroom remodel, bring your vanity width, ceiling height, and a photo of the wall to our Scottsdale showroom, or Northside Lighting in Tucson, and we can lay out the mirror and lighting together.