How wide should a bathroom mirror be?

It should not be wider than the sink, but usually about 2 to 4 inches narrower. A common choice is to pick a mirror that's 4 inches narrower than the sink. So for a sink with a width of 36 inches, you would want a mirror with a width of 32 inches.

How do you calculate the height of the mirror above the sink?

Add twelve inches to the height of your vanity and subtract that number from the ceiling height. If you have a 36-inch tall vanity with a 96-inch ceiling, subtracting 48 from 96 gives you a mirror height of 48 inches.

What size should a round mirror be for a sink that is 30 inches high?

The diameter is approximately 26 inches. Round mirrors follow the same rules as rectangular ones so the diameter should be about four inches smaller than the width of your sink.

What size should a mirror be for a double sink?

If you're using a single mirror that covers both sinks, the width of the mirror should be four inches narrower than the vanity. If you're using two separate mirrors, subtract eight inches from the width of the vanity and divide that resulting number by two to get the width for each mirror. So for a 60-inch wide vanity, two mirrors about 26 inches wide with four inches in between would be ideal.

How high should a bathroom mirror be?

Typically, the bottom edge of the mirror is placed about 5 to 10 inches above the faucet with the center being at eye level. The height should be around 60 to 65 inches from the floor. In handicap accessible bathrooms, the bottom edge of the reflective surface must not be more than 40 inches from the floor.

Bathroom Mirror Size Calculator

Your bathroom

What are you sizing?

Pick the mirror shape and vanity layout you are planning.

Rectangular mirror

Round mirror

Double vanity

Vanity or sink width

Vanity height

Ceiling height

Recommended mirror size

Mirror width

Mirror height

Recommended mirror width

Keep the mirror no wider than the vanity itself, and up to about 4 in (10 cm) narrower. Anything wider looks unbalanced and crowds the wall lights.

Placement and sizing tips

Hanging height: the bottom edge of the mirror usually sits 5 to 10 inches above the faucet, and the mirror is centered near eye level, roughly 60 to 65 inches from the floor.

Accessible bathrooms: under the ADA, a mirror above a sink has the bottom edge of its reflecting surface no higher than 40 inches above the floor.

Lighting and layout: leave room on the wall for sconces or a light bar, and keep the mirror clear of the faucet and any backsplash so it does not crowd the vanity.

The size of the bathroom mirror is determined not by the entire wall but rather by the sink below. This calculator allows you to determine the recommended width and height for a rectangular mirror, diameter for a round mirror or layout for a double sink by entering some dimensions.

How to determine the size of the mirror:

There is a simple design rule for the width of the mirror. In general, the mirror that goes above the sink should not be wider than the sink itself. It usually looks best if it's two to four inches narrower. A common choice is a difference of four inches:

\text{Mirror width} = \text{Vanity width} - 4\ \text{in}

To ensure there is enough clearance between the top of the sink and the ceiling, add twelve inches to the height of your sink and subtract that from the height of your ceiling.

\text{Mirror height} = \text{Ceiling height} - (\text{Vanity height} + 12\ \text{in})

The same four inch rule also applies to the diameter of a round mirror so that it is about four inches smaller than the width of your sink.

Examples of calculations.

Let's take a sink that is 36 inches wide and 36 inches high, and let's say the room has a ceiling height of 96 inches. The width would be calculated by subtracting 4 from 36 which gives us 32 inches. The height would be calculated by subtracting 36 from 96 and adding 12 to it which gives us 48 inches (so 96 minus 48). So for this sink, a mirror that is about 32 inches wide and 48 inches tall would work well.

36 - 4 = 32\ \text{in} \qquad 96 - (36 + 12) = 48\ \text{in}

Common sizes of washbasin cabinets:

These widths are based on the 'four inch' rule applied to a single mirror. For double sink undermounts, the total width is split between two mirrors.

Vanity width	Single mirror width	Round mirror diameter
24 in	20 in	20 in
30 in	26 in	26 in
36 in	32 in	32 in
48 in	44 in	44 in
60 in	56 in	—
72 in	68 in	—

Double sink under-counter units:

For double sink vanity cabinets wider mirrors are required but the principle is the same. If you use one large mirror that covers both sinks then reduce the width by four inches from the cabinet's width. If you prefer two separate mirrors mount one above each sink and inset them by two inches on either side leaving a gap of four inches between the two mirrors. The cabinet's width will therefore be reduced by eight inches which is divided between the two mirrors:

\text{Each mirror} = \frac{\text{Vanity width} - 8\ \text{in}}{2}

A double sink vanity with a width of 60 inches will give you two mirrors that are about 26 inches wide each, leaving a decent amount of space in the middle. Designers often choose rectangular mirrors for double sink vanities as this helps to align both mirrors aesthetically.

Assembly location and height:

After you have determined the size, you need to mount the mirror at the right place. If you position it in the middle of the sink instead of on the edge of the countertop, then the reflection will be centered. The bottom edge of the mirror should usually be placed 5 to 10 inches above the faucet with the center being eye level. This is equivalent to a height of about 60 to 65 inches from the floor.

ADA (Americans with Disabilities Act) has clear guidelines for handicap accessible bathrooms. The bottom edge of the reflective surface of a mirror mounted above a sink must be no more than 40 inches from the floor. Make sure there is enough space to mount a wall light on either side or above, and avoid having the mirror touch the faucet or back wall.

These are guidelines for design and not strict rules. Measure your space, check the position of the mirror in relation to lighting and fixtures, and adjust as necessary before you buy or install it.

Frequently asked questions

How wide should a bathroom mirror be?: It should not be wider than the sink, but usually about 2 to 4 inches narrower. A common choice is to pick a mirror that's 4 inches narrower than the sink. So for a sink with a width of 36 inches, you would want a mirror with a width of 32 inches.
How do you calculate the height of the mirror above the sink?: Add twelve inches to the height of your vanity and subtract that number from the ceiling height. If you have a 36-inch tall vanity with a 96-inch ceiling, subtracting 48 from 96 gives you a mirror height of 48 inches.
What size should a round mirror be for a sink that is 30 inches high?: The diameter is approximately 26 inches. Round mirrors follow the same rules as rectangular ones so the diameter should be about four inches smaller than the width of your sink.
What size should a mirror be for a double sink?: If you're using a single mirror that covers both sinks, the width of the mirror should be four inches narrower than the vanity. If you're using two separate mirrors, subtract eight inches from the width of the vanity and divide that resulting number by two to get the width for each mirror. So for a 60-inch wide vanity, two mirrors about 26 inches wide with four inches in between would be ideal.
How high should a bathroom mirror be?: Typically, the bottom edge of the mirror is placed about 5 to 10 inches above the faucet with the center being at eye level. The height should be around 60 to 65 inches from the floor. In handicap accessible bathrooms, the bottom edge of the reflective surface must not be more than 40 inches from the floor.

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Disclaimer: This calculator is provided for general informational and educational purposes only. Our calculators are under active development, and results may be inaccurate, incomplete, or unsuitable for your situation. Always verify the figures independently and seek advice from a qualified professional before relying on them. We make no warranties and accept no liability for any loss or decision arising from use of this tool.

References

U.S. Access Board — Chapter 6: Toilet Rooms (Mirrors)
Official guidance on the 40-inch mirror mounting height in the ADA Standards (603.3).
2010 ADA Standards for Accessible Design
U.S. Department of Justice accessibility standards, including section 603.3 on mirrors.