Why the Right Bathroom Mirror Size Matters
The correctly sized bathroom mirror can transform the entire look and feel of your bathroom, making it more aesthetically pleasing and functional. Getting it wrong, however, can have the opposite effect — making the space feel cramped or unbalanced. Our Bathroom Mirror Size Calculator helps you find the perfect dimensions for any vanity setup in seconds.
What Size Should a Bathroom Mirror Be?
A bathroom mirror should never be wider than your vanity. The ideal width is 4 to 6 inches narrower than the vanity width — this framing effect creates a visually balanced look. For height, the mirror should sit 6–10 inches above the vanity top and finish at least 6 inches below the ceiling to leave breathing room.
For very tall people, a taller mirror is especially important to avoid the "cut off head" effect. A taller mirror also makes the bathroom appear larger and more open.
How to Use This Bathroom Mirror Size Calculator
Using our calculator is straightforward:
- Select your measurement system — Imperial (inches) or Metric (centimeters).
- Choose your mirror type — Rectangular, Circular (round), or Double Vanity.
- Enter your vanity width — the full width of your bathroom vanity or sink cabinet.
- Enter your vanity height — the height from the floor to the top of the vanity surface.
- Enter your ceiling height — the total height of the room from floor to ceiling.
- Optional: Enable cost estimation and enter the price per square foot (or square meter) plus your preferred currency to get an estimated mirror cost.
The calculator will instantly show you the recommended mirror width range, mirror height, mounting height (distance from floor to the bottom of the mirror), mirror area, and an optional cost estimate.
Mirror Size Guide by Vanity Type
Single Rectangular Vanity
For a standard single vanity, select Rectangular. The calculator subtracts 4–6 inches from your vanity width to give you a min–max width range. The height spans from ~8 inches above the vanity to 6 inches below the ceiling.
Round / Circular Mirror
Round mirrors are popular in modern and boho-style bathrooms. Select Circular and enter your vanity dimensions. The calculator recommends a diameter range based on vanity width and available vertical space. For unusual shapes (hexagonal, oval, star), use the circular option with the largest fitting dimension.
Double Vanity
For a double vanity, you have two common options: one large mirror spanning both sinks, or two individual mirrors centered over each sink. Our calculator covers the two-mirror approach. Select Double Vanity to get the recommended width for each individual mirror, with a 4 in (10 cm) gap between them.
Mounting Height Reference
The mounting height shown in the results is the distance from the floor to the bottom edge of the mirror. This is the most important measurement when marking your wall for installation. Aim for a mounting height of about 6–10 inches above the vanity top for most adults.
Frequently Asked Questions
What size mirror should I use for a 36-inch vanity?
For a 36-inch vanity, the ideal mirror width is 30–32 inches. This keeps the mirror 4–6 inches narrower than the vanity on each side, creating a balanced and finished look.
What size round mirror for a 30-inch vanity?
A round mirror with a diameter of 24–26 inches works well for a 30-inch vanity. This gives a proportional look while leaving visual space on the sides.
Can a mirror be wider than the vanity?
It is generally not recommended. A mirror wider than the vanity can look out of proportion and may conflict with side wall features like light fixtures or cabinetry. Stick to mirrors that are at least 4 inches narrower than the vanity.
How high should the mirror be above the vanity?
Mount the mirror so its bottom edge is 6–10 inches above the vanity countertop. The top edge should be at least 6 inches below the ceiling (or below any overhead cabinetry or light fixtures).
Does mirror size affect how bright my bathroom looks?
Yes. A larger mirror reflects more light, which can make a small bathroom feel significantly brighter and more spacious. If your bathroom lacks natural light, consider using a taller mirror to maximize the reflective effect.