Bathroom Mirror Size Calculator
Enter your vanity width, ceiling height, and counter height to find the recommended mirror width and height. Choose between single, double, or circular mirrors, pick a style, add your faucet and lighting clearances, and see the full sizing math in the steps panel. Switch between inches and centimetres at any time.
How to size a bathroom mirror
The most reliable starting point is the 75% rule: a single bathroom mirror should be approximately 75% of the vanity width. A 36-inch vanity calls for a mirror about 27 inches wide, and a 60-inch vanity calls for roughly 45 inches. This leaves a small margin on each side that visually frames the mirror without making it look small or awkward. For height, the mirror sits between two fixed points: the bottom edge clears the tallest faucet by at least 1 inch, and the top edge stays 4-6 inches below the ceiling or any overhead light. Your actual available height depends on your specific clearances, which is why the calculator uses your own measurements rather than a generic rule.
Single, double, arched, and circular mirrors
Different mirror shapes use different sizing ratios. Rectangular single mirrors follow the 75% width rule. Circular and oval mirrors look best at about 60% of the vanity width, because a circle takes up less visual area than a rectangle of the same width. Arched mirrors use 70% - the arch needs more base width to read as dramatic rather than narrow. For a double vanity with two individual mirrors, each mirror centers over its own basin; the calculator subtracts a center gap of 4 inches (10 cm) and outer edge margins, then divides the remaining width in two. A single wide mirror over a double vanity uses 85% of the total width for a spa-like continuous look.
Eye level and mounting height
Design guidelines recommend placing the mirror center at 60-65 inches (152-165 cm) from the floor, which is comfortable eye level for most adults standing at the sink. The calculator shows you the center height as an output so you can check this directly. If the result falls outside the 57-65 inch (145-165 cm) range, adjust the gap above the vanity or the ceiling clearance to bring it into range. In households with a wide range of heights, centering at 60 inches works for the widest range of people. For powder rooms and guest baths that are rarely used for daily grooming, you have more flexibility.
Side sconce spacing
- Vertical sconce bars require 3-7 inches (8-18 cm) of clear wall on each side of the mirror. If you plan to add sconces, the calculator deducts this from the mirror width so the mirror does not overlap the fixtures.
- The sconce center-to-center output tells you how far apart to mount the two sconce boxes, measured from the center of one fixture to the center of the other.
- Overhead-only lighting: no sconce pad needed, but the mirror top edge should still stay at least 4-6 inches below any overhead can or flush fixture to avoid glare.
- Backlit or LED-framed mirrors combine both functions and can typically be sized the same as a standard rectangular mirror.
Vanity width to mirror size guide
| Vanity width | Mirror width (single) | Each mirror (double) | Circular diameter | Notes |
|---|---|---|---|---|
| 24 in / 61 cm | 18 in / 46 cm | N/A | 14 in / 36 cm | Powder room or small single |
| 30 in / 76 cm | 22 in / 56 cm | N/A | 18 in / 46 cm | Standard single bath |
| 36 in / 91 cm | 27 in / 69 cm | N/A | 22 in / 56 cm | Common single vanity |
| 48 in / 122 cm | 36 in / 91 cm | 17 in / 43 cm each | 29 in / 74 cm | Narrow double or wide single |
| 60 in / 152 cm | 45 in / 114 cm | 23 in / 58 cm each | 36 in / 91 cm | Standard double vanity |
| 72 in / 183 cm | 54 in / 137 cm | 29 in / 74 cm each | 43 in / 109 cm | Large double vanity |
| 84 in / 213 cm | 63 in / 160 cm | 35 in / 89 cm each | 48 in / 122 cm | Extra-wide double |
Recommended mirror dimensions by vanity size. Width uses 75% rule for single mirrors; height assumes 96 in / 244 cm ceiling, 34 in / 86 cm counter, 8 in / 20 cm faucet, 6 in / 15 cm ceiling gap.
Frequently asked questions
What is the standard rule for bathroom mirror width?
The most widely used guideline is 75% of the vanity width for a single rectangular mirror. This leaves about 12-13% of the vanity width as margin on each side, which keeps the mirror proportional without looking small. For a double vanity with two mirrors, each mirror is sized to its own basin using a similar approach, with a 4-inch (10 cm) gap between the two. Circular mirrors use a smaller ratio - about 60% - because circles occupy less visual space than rectangles of the same width.
How wide should a mirror be over a 36-inch vanity?
For a 36-inch vanity, the 75% rule gives you a mirror about 27 inches wide, leaving roughly 4.5 inches of margin on each side. In practice, anything from 24 to 32 inches wide looks balanced. Go narrower (24-26 inches) if you are adding sconce lights on the sides, and wider (30-32 inches) for a more modern frameless look with no side fixtures. A circular mirror over a 36-inch vanity works well at 22-24 inches in diameter.
How high above the vanity should a bathroom mirror be hung?
The mirror bottom edge should sit at least 1 inch above the highest point of the faucet spout to avoid splashing and visual crowding. In practice, many designers use 5-8 inches above the counter top for low-profile faucets. The top edge should stop 4-6 inches below the ceiling or any overhead light fixture. The most important check is the center height: it should land between 57 and 65 inches from the floor for comfortable eye level.
What is the best mirror size for a 60-inch double vanity?
For a 60-inch double vanity you have two good options. Two individual mirrors, each about 23 inches wide, centered over each basin with a 4-inch gap between them, give independent use and a clean look. One wide mirror at about 51 inches (85% of 60 inches) creates a seamless spa-like appearance. The two-mirror option is preferred in most design guides because it allows two people to use the space at the same time and avoids the visual weight of one very large panel.
How much clearance do I need for sconces next to a mirror?
Standard vertical sconce bars need at least 3-5 inches (8-13 cm) of clear wall between the mirror edge and the center of the sconce. Wide globe or lantern sconces may need 6-8 inches (15-20 cm). The calculator lets you select narrow (3 in), standard (5 in), or wide (7 in) sconce pads, which are automatically subtracted from the recommended mirror width. This prevents the common mistake of ordering a mirror that overlaps the fixture boxes after installation.
Can a bathroom mirror be wider than the vanity?
It is generally not recommended, because a mirror wider than the vanity can cover electrical outlets, light switches, or trim, and the overhanging edges can look unbalanced. The main exception is a deliberate full-wall or edge-to-edge mirror, which works in modern and minimalist bathrooms to visually expand a narrow space. If you go wall-to-wall, use a frameless design and ensure there is at least 1 inch of clearance from the mirror edge to any outlet or switch plate.
What size circular mirror fits over a standard vanity?
A good starting point is 60% of the vanity width, which accounts for the fact that a circle covers less area than a rectangle of the same width. For a 30-inch vanity, that is about an 18-inch diameter; for a 36-inch vanity, about 22-24 inches; for a 48-inch vanity, about 29 inches. Circular mirrors are most common over single-sink vanities. Practical upper limits are around 36-40 inches diameter, as larger circles become visually overwhelming over a standard sink.