πͺ Bathroom Mirror Size Calculator
The right mirror width, height, and hanging spot for your vanity.
Recommended Mirror
How to Use This Bathroom Mirror Size Calculator
The designer rule is simple: your mirror should be 70 to 80 percent as wide as your vanity, hung with its center near eye level. Enter your vanity width and the available wall height above the counter, and the calculator returns the ideal mirror width range, a sensible height, and hanging guidance.
Measure your vanity width in inches, edge to edge. For a double vanity, measure the whole unit unless you plan two separate mirrors.
Measure the wall space from the top of the backsplash to the bottom of the light fixture or ceiling, whichever is lower.
Hit Size My Mirror. You get the target width range, a recommended height that fits the space, and the hanging height.
Shop within the range. If you fall between standard sizes, round down; a slightly smaller mirror always looks more deliberate than a slightly big one.
The Sizing Rules
The 70 to 80 percent rule is the one designers cite most because it keeps the mirror visually anchored to the vanity without matching it exactly. A mirror the same width as the vanity can work in modern minimal bathrooms, but it leaves no margin for error. Height is more flexible: fill the available wall space attractively, keeping the bottom edge high enough to clear the faucet splash zone.
Worked Example
A 48-inch vanity with 36 inches of wall space above the backsplash: 48 x 0.70 = 33.6 and 48 x 0.80 = 38.4, so the target width is 34 to 38 inches. A standard 36-inch mirror fits perfectly. For height, leave 6 inches above the faucet and 3 inches below the light fixture, giving about 27 inches of mirror height in the 36-inch space. Hung with its center at 60 inches from the floor, the mirror spans roughly 46.5 to 73.5 inches, a comfortable view for users from about 5 feet to 6 feet 2 inches tall.
Single vs Double Vanity Layouts
For a single vanity, one centered mirror following the 70 to 80 percent rule is the safe choice. For a double vanity, decide between one wide mirror and two individual mirrors before you shop, because the lighting plan differs. One wide mirror, say 48 inches over a 60-inch double vanity, needs a long light bar or two sconces flanking it. Two mirrors, each 20 to 24 inches over a 60-inch vanity, each get their own sconce pair or a short bar above. Two mirrors cost more but look custom and end the morning bottleneck over who gets the reflection.
Mistakes That Ruin the Look
The classic error is the mirror that is exactly vanity width, which reads as a slab rather than a design choice. Another is hanging too high: if the shortest regular user cannot see their full face, it is too high, no matter what the tape measure says. Tiny mirrors over big vanities look lost; when in doubt between two sizes, the larger one usually wins as long as it stays under 80 percent of the vanity. And do not forget the frame: a 2-inch frame on each side eats 4 inches of glass, so a 36-inch framed mirror shows like a 32-inch one. Size the glass, not the frame.
A Second Worked Example: The Double Vanity
A 72-inch double vanity, two sinks. Option one: two separate mirrors, each centered over a 36-inch zone. Per mirror: 36 times 0.70 to 0.80 is 25 to 29 inches wide. Two 28-inch mirrors with a few inches between them look tailored and give each user their own. Option two: one big mirror, 72 times 0.70 to 0.80 is 50 to 58 inches. One 54-inch mirror is simpler and cheaper, but it turns the vanity into a single visual unit and both users share the reflection.
Designers usually prefer the pair for double vanities: it defines two stations and lets each mirror center on its user. The single mirror wins in small or modern-minimal bathrooms where simplicity matters more. Either way, the 70-to-80 percent rule applies per mirror zone, not just per vanity.
Round vs. Rectangular vs. Arched
Shape changes the feel as much as size. Rectangular mirrors are the default: maximum reflective area, easy to size by the percentage rule. Round mirrors soften a bathroom full of hard rectangles and suit pedestal sinks beautifully, but the width rule still applies to the diameter. Arched mirrors add a sense of height and a traditional touch; size them by width at the widest point.
Round mirrors need a hanging decision rectangles avoid: one centered mirror over a single sink, hung with its center at eye level. They also pair well with sconces on both sides, since there are no corners to fight. Whatever the shape, keep the bottom edge 5 to 10 inches above the faucet and the center near 60 inches from the floor. Geometry varies; eye level does not.
Common Mirror Mistakes
First: the too-small mirror. A 24-inch mirror on a 60-inch vanity looks like an afterthought; the 70 percent floor exists because smaller reads as a mistake. Second: hanging too high. The center belongs near eye level, about 60 inches from the floor; mirrors hung for the tallest household member leave everyone else staring at their forehead.
Third: ignoring the lights. A mirror that runs into the light bar, or sits so high the lights glare off its top edge, was measured without looking up. Measure the full wall: backsplash to fixture. Fourth: the medicine-cabinet surprise. Recessed cabinets need wall depth and no plumbing or wiring in the way; check before falling in love with one. Fifth: no side clearance for sconces. Sconces want a few inches beside the mirror; a mirror at 95 percent of vanity width leaves them nowhere to live.
A Second Worked Example: The Powder Room Statement
A powder room vanity is 24 inches wide, small, with no storage needs. The rule of thumb says the mirror should be 70 to 80 percent of the vanity width: 24 times 0.75 is 18 inches. But powder rooms are where design takes risks, so go bold: a 22-inch round mirror, nearly the full vanity width, hung 6 inches above the backsplash. The oversized round shape makes the tiny room feel twice as big, and there is no daily grooming routine to interfere with.
Height matters more here than width. Center the mirror at eye level, about 60 inches from the floor to the center, and keep the bottom edge at least 4 inches above the faucet's highest point to dodge splashes. In a powder room, the mirror is art that happens to reflect; size it for impact, mount it for faces, and let the small vanity break the 70-percent rule in the direction of drama.
The 70-Percent Rule and When to Break It
The standard guidance, mirror width 70 to 80 percent of vanity width, exists to create a visual margin: a few inches of wall on each side so the mirror reads as an object, not a wall covering. For a 48-inch vanity, that is 33 to 38 inches of mirror. It works because it balances the vanity visually without overwhelming the plumbing wall.
Break it deliberately in three cases. One: double sinks, where two mirrors each 70 percent of their half look better than one giant span. Two: very narrow vanities under 30 inches, where a full-width mirror opens the room. Three: intentional drama, a floor-to-ceiling mirror in a modern bath. The rule is a default, not a law; break it for a reason you can name, not by accident at the store.
Lighting and Mirrors: The Partnership
A perfectly sized mirror with bad lighting is a daily annoyance. Sconces at eye level on both sides, about 36 to 40 inches apart for a single mirror, eliminate the shadows that overhead lights carve under your eyes and chin. The mirror should sit between the sconces, not above or below them; light crossing the face sideways is what flatters.
Backlit mirrors solve the wiring problem elegantly: the light source rings the mirror itself, so placement is automatic. Size the backlit mirror slightly larger than the 70-percent rule suggests, since the glow needs wall space to read as a halo. And match color temperature to the rest of the bath: 2700K warm for relaxing, 3000K neutral for accurate makeup. A mirror that shows you in a different color temperature than the bedroom mirror will start arguments about which one lies.
Measuring for Medicine Cabinets and Recessed Mirrors
Recessed mirrors add a rough-opening constraint. A 20-by-30-inch recessed cabinet needs a wall cavity at least that big between studs, and standard 16-inch on-center framing gives 14.5 inches of clear space, which will not fit a 20-inch cabinet without reframing. Measure the stud bay before buying, not after, and check for plumbing and wiring in the cavity with a stud finder that detects both.
Surface-mount cabinets dodge the framing issue but project 4 to 6 inches from the wall, which changes the effective mirror position relative to the faucet. Keep at least 6 inches between the cabinet bottom and the backsplash for splash clearance, and confirm the door swing clears the faucet handles. The calculator sizes the visible mirror; the wall decides whether it recesses or mounts, and the wall always wins the argument.
Frequently Asked Questions
What size mirror should I get for my vanity?
Choose a mirror 70 to 80 percent as wide as your vanity. A 48-inch vanity pairs with a 34 to 38-inch mirror. Going slightly narrower than the vanity looks intentional; going wider looks like a mistake. The calculator above gives the exact range for your vanity width.
How high should a bathroom mirror hang?
Hang the mirror so its center sits at average eye level, about 60 inches from the floor, with the bottom edge 5 to 10 inches above the faucet or backsplash. In a household with big height differences, favor the primary user or choose a taller mirror that covers everyone.
Should a bathroom mirror be wider than the sink?
Usually it matches the sink or vanity, not exceeds it. A mirror wider than the vanity throws off the balance and can look like it belongs to a bigger room. The one exception is a full-wall mirror in a small bathroom, which is a deliberate style choice that makes the space feel larger.
Round or rectangular mirror for a bathroom?
Rectangular mirrors suit most vanities because they echo the vanity shape and maximize usable reflection. Round mirrors soften modern bathrooms and work well over pedestal sinks or as a pair over a double vanity. Match the mirror shape to the room, not just the trend.
How big should a mirror be over a double vanity?
You have two good options: one large mirror spanning 70 to 80 percent of the total vanity width, or two separate mirrors, each centered over its sink and sized 70 to 80 percent of each sink base. Two mirrors give each person their own space and look more custom.
Can a bathroom mirror be too big?
Yes. A mirror that overwhelms the vanity makes the bathroom feel like a funhouse and shows every splash and smudge at scale. If the mirror is wider than the vanity or taller than the space between counter and light fixture, size down. Bigger is not better past the 80 percent rule.
Where should vanity lights go with a mirror?
Sconces mounted at eye level on either side of the mirror give the most flattering light, about 36 to 40 inches apart for a single sink. A bar light above the mirror should be about 75 percent of the mirror width and sit 3 to 6 inches above the mirror top.
How do I measure for a bathroom mirror?
Measure the vanity width first, then multiply by 0.7 and 0.8 for your target mirror width range. Measure the wall space from the backsplash to the light fixture or ceiling for max height. Note faucet height too, since the mirror bottom needs 5 to 10 inches of clearance above it.