Calculate the ideal bathroom mirror dimensions for your vanity. Get width, height, and mounting height recommendations based on vanity size and user height.
Choosing the right bathroom mirror size is one of the most overlooked details in a bathroom remodel, and one of the easiest to get wrong. A mirror that is too small looks lost above the vanity, while one that is too wide overwhelms the space.
The standard rule of thumb is that a bathroom mirror should be 2-6 inches narrower than the vanity on each side, giving the mirror a width of about 70-90% of the vanity width. Height depends on the tallest user and ceiling clearance, typically 30-42 inches for standard ceilings. The bottom edge should sit 5-10 inches above the countertop, or about 40 inches from the floor for a wall-mounted sink.
This calculator takes your vanity dimensions, ceiling height, and tallest user's height to recommend the ideal mirror size and mounting position. It handles single and double vanities, framed and frameless mirrors, and provides specific width, height, and placement measurements.
A properly sized bathroom mirror is the centerpiece of the vanity area. This calculator applies practical interior-design proportions to give you width, height, and mounting guidance before you buy.
It is useful because mirror size affects both function and the feel of the room. Getting the width and mounting height right avoids a mirror that is too cramped, too tall, or awkwardly close to the ceiling.
Mirror width = Vanity width × 0.70 to 0.90 (centered). Mirror height = (Eye level + 2") - (Counter height + 6") - typically 30-42". Bottom edge = Counter height + 4-8". Top edge should not reach within 4" of ceiling.
Result: Mirror: 36" wide x 36" tall, mount bottom at 42"
For a 48" vanity: ideal width is 48 x 0.75 = 36". Counter at 36" + 6" gap = 42" bottom edge. Tallest user eye level at ~65" + 2" = 67" top edge. Height = 67 - 42 = 25", rounded up to standard 30" for good proportion. Framed adds 2" visible width.
Interior designers follow the vanity proportion rule: the mirror should be at least 2 inches narrower than the vanity on each side, but not so narrow that it feels disconnected. For a 60" vanity, this means a 50-54" mirror is ideal. Going below 42" on a 60" vanity creates a lost, undersized look.
The mirror should be tall enough that the tallest household member can see their entire head and shoulders. For most people, a 30" tall mirror is sufficient. However, 36" provides more comfort, and 40-42" creates a dramatic, luxurious feel. The top of the mirror should not come within 4 inches of the ceiling.
For double vanities (60"+), you have two approaches: a single large mirror spanning most of the vanity width, or two identical mirrors centered over each sink. Two mirrors work best when the vanity has clear visual separation (two distinct countertop areas or a cabinet tower in the center). A single mirror creates a more open, modern look.
Ideally 70-90% of vanity width. A 48" vanity looks best with a 34-42" mirror. Never go wider than the vanity.
Leave 4-8 inches between the countertop or backsplash and the bottom of the mirror. 5-6 inches is the most common spacing.
Use two mirrors - each should be 70-80% of the individual sink section width, centered over each sink. Leave 4-8 inches between mirrors.
Standard is 40-42 inches from floor to bottom edge. Adjust based on counter height: counter + 5-6 inches gap.
No - leave at least 4 inches between the top of the mirror and the ceiling. Floor-to-ceiling mirrors are a design exception.
A framed mirror's visible glass is smaller than the outer dimension. Measure the frame and subtract it from width and height to ensure the glass area meets recommendations.