So you are making home improvements, and you need to calculate the bathroom mirror size to get that look just right. Well, we have just what you need. Our bathroom mirror size calculator will help you choose the correct mirror to suit your needs.

Keep reading to learn:

  • Why it is essential to have the right bathroom mirror for your vanity?
  • What size should a bathroom vanity mirror be?
  • What size round mirror for a 30-inch vanity?
  • How to determine the mirror size for your bathroom; and
  • How to use our bathroom mirror size calculator.

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The importance of having the right bathroom mirror for your vanity

The correctly sized bathroom mirror can improve the look of your entire bathroom, making it more aesthetically pleasing to the eye. However, getting it wrong can have the opposite effect. As such, when buying a bathroom mirror, you first need to know the correct size to suit your needs.

Of course, a few things may affect your ability to choose your vanity mirror size. If there is a light in the area where you plan to mount your mirror, you will need to ensure the light will be above the level of the mirror. Additionally, if there is a cupboard above your vanity, you may add the mirror to the doors, or if there are multiple doors with space between them, this area may be suitable.

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So what size should a bathroom mirror be?

Have you been wondering how to determine the mirror size for your bathroom? It is simple. A bathroom mirror should not be greater than the width of your vanity. In fact, 4 to 6 inches narrower than the width of your bathroom vanity is the ideal width for your mirror.

Picture showing how to measure for a single vanity.

Additionally, choosing the correct height is extremely important, especially if you are very tall. This is because, for tall people, the wrong length of bathroom mirrors can affect their ability to see themselves correctly. For instance, when using a short mirror, a tall person may have his head cut off. As such, it is best to have a mirror 6 inches below your ceiling level and 6 to 10 inches above your vanity.

Another reason for having a tall mirror for your bathroom is because it makes the area appear more open.

How to use our bathroom mirror size calculator

To use our bathroom mirror size calculator, you need first to:

  1. Choose the type of mirror you intend to buy.

    The options available are either circular, rectangular, or double. We know other options are available, and you can also choose from these. Use the shape that best relates to the more unusual styles. For instance, you may use the circular calculator if buying a hexagon-shaped mirror.

    The same applies if you wish to buy a mirror shaped like a star. Measure the diameter of the mirror you want to purchase and use this with the circular calculator.

    For an oval shape mirror whose height is the longer side, use the rectangular calculator to do your calculation.

  2. Enter the height and width of the vanity.

  3. Add the height of the ceiling. This must be a value greater than the height of the vanity plus an additional eight inches because only then will there be enough space to fit a mirror.

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How do I go about calculating the correct size vanity mirror for my bathroom?

To calculate the correct size rectangular mirror for your bathroom, follow these steps:

  1. First, measure the height of the ceiling.
  2. Get the height and width of your vanity.
  3. Subtract 4 inches from the width of the vanity. This is the width of your mirror.
  4. Add 12 inches to the height of your vanity. Subtract the answer from the height of your ceiling.
  5. This is the height of your mirror.

What size mirror should I use for a double vanity?

Double vanities are quite lovely for bathrooms, and they require larger mirrors. However, even for this, four inches smaller than the width of the vanity is still the standard. Unlike single vanities, however, it is recommended that you stick with rectangular mirrors for your double vanity.

Some people may opt to use two mirrors instead of one. So what size bathroom mirror should we choose in this instance?

This image shows how to determine the correct size mirror for your double vanity.

To calculate the correct size double mirror for your vanity:

  1. Find the height of the vanity.
  2. Measure the height of the ceiling.
  3. Measure the width of the vanity.
  4. Add the height of the vanity plus 12 inches. Subtract this from the height of the ceiling. The result gives you the height of the mirror.
  5. Subtract 8 inches from the vanity's width to calculate the mirror's width.
  6. When hanging these mirrors, mount them 2 inches from the edge of the vanity on either side. That will leave a 4-inch space between them. It will give your bathroom area a balanced feel.


What size vanity mirror should I buy for a 36 inch wide bathroom vanity?

For a bathroom vanity that is 36 inches wide and 36 inches high in a room whose ceiling is 96 inches tall, the height of the vanity mirror should be:

Height of the ceiling - (Height of the vanity + 12 inches)

In this case that is 96 - (36 + 12) = 48 inches.

What size round mirror should I use for a 30-inch vanity?

A mirror that is 26 inches in diameter.

To determine what size round mirror to use for a 30-inch vanity:

  1. Subtract 4 inches from 30. That leaves 26 inches.
  2. This is the diameter of the mirror that best suits this vanity.

How big should a mirror over a bathroom vanity be?

A mirror placed over a bathroom vanity should be the width of the vanity or 2 to 4 inches smaller.

A mirror over a bathroom vanity should be no wider than the vanity itself. Additionally, it should be no more than four inches narrower than the width of the vanity.

Adena Benn
How to layout and cut the fabric for your project.
Type of bathroom mirror
Height of vanity
Height of ceiling
Diameter of mirror
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