How to Measure for a Bathroom Mirror

Going through the looking-glass starts with the right measurements

Luxury bathroom with a tiled walk-in shower
Photo: Joe Hendrickson / iStock / Getty Images Plus / Getty Images
Luxury bathroom with a tiled walk-in shower
Photo: Joe Hendrickson / iStock / Getty Images Plus / Getty Images
Highlights
  • The standard bathroom mirror size is 24 by 36 inches.

  • Bathroom mirror sizes can vary from 15 to 60 inches wide by 20 to 48 inches high.

  • Where you install your bathroom mirror affects the mirror size.

  • Some bathrooms use one large mirror, while others need multiple mirrors.

  • Work with a mirror installer for the most accurate measurements.

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The right size bathroom mirror can transform a bathroom into an open, seemingly larger space. But knowing exactly what mirror size you need isn’t always so straightforward. It can quickly start to feel like a long-forgotten high school geometry problem if you don’t know what to look for. We’ve rounded up standard bathroom mirror sizes to help you learn how to measure a bathroom mirror.

What Is the Standard Bathroom Mirror Size?

The standard bathroom mirror size is 24 inches wide by 36 inches high. However, bathroom mirrors can range in size depending on where you’re installing the mirror. Overall sizes vary from as little as 15 inches wide to as much as 60 inches wide and 20 inches to 48 inches in height.

Bathroom Mirror Size by Type

Since the type of bathroom mirror impacts the size, you’ll want to base your mirror measurements on the type of mirror rather than simply choose the standard mirror size. Refer to this chart to help you determine which mirror size best fits your bathroom:

Type of Bathroom MirrorWidth (in)Height (in)
Bathroom Vanity18–4028–48
Double Bathroom Vanity60–7228–48
Medicine Cabinet15–2420–36
Double Medicine Cabinet30–4620–36
Triple Medicine Cabinet30–6020–36

Bathroom Vanity Mirror 

One of the most common mirrors for a bathroom is a vanity mirror. Dimensions for this mirror type range from 18 inches to 40 inches wide by 28 to 48 inches high. Depending on the orientation of your bathroom, you may choose to hang a vanity mirror that’s taller than it is wide, wider than it is tall, or even a round mirror for a classic touch. 

Double Bathroom Vanity Mirror

If you have a Jack and Jill vanity, you’ll need a larger mirror for your bathroom than a single vanity. Sizes for a double bathroom mirror vary from 60 to 72 inches wide by 28 to 48 inches tall. Some homeowners end up using one mirror in front of each sink. In this case, you may end up choosing two mirrors with slightly narrower single-vanity dimensions.

Medicine Cabinet Mirror

If your medicine cabinet doesn't come with built-in mirrors, installing mirrors on your medicine cabinet is a great way to open up the space. Medicine cabinet mirrors typically have the smallest dimensions of all the bathroom mirror sizes, ranging from 15 to 24 inches wide by 20 to 36 inches in height. 

Double Medicine Cabinet Mirror

Some medicine cabinets contain two cabinets. The average dimensions for a double medicine cabinet are 30 by 46 inches wide by 20 to 36 inches high. However, you’ll need two mirror panels—one for each cabinet door. To get accurate measurements, measure each cabinet door rather than taking the full dimensions of the cabinets and dividing them in two. Some double cabinet doors differ in size.

Triple Medicine Cabinet Mirror

Just like double medicine cabinets, triple medicine cabinets contain multiple panels and therefore need three separate mirrors. The average triple medicine cabinet is 30 to 60 inches wide by 20 to 36 inches tall, but again, measure each cabinet to figure out the correct measurements for each mirror.

How to Measure the Right Size Bathroom Mirror

A general interior view of a small bathroom
Photo: John Keeble / Moment / Getty Images

Measuring the area around the installation site can help you pick a bathroom mirror size that complements the space. Follow these three tips on measuring the right bathroom mirror dimensions. 

  1. Consider the installation site. Overall, a bathroom vanity needs a mirror that is slightly shorter than the total length of the vanity. A good rule of thumb is to choose a mirror that is a few inches shorter in width than the vanity, noticeably wider than your sink, and tall enough to show your full face and torso.

  2. Use accurate measurements. If you’re installing medicine cabinet mirrors or a mirror in a location where space is limited, such as between two cabinets, you must take accurate measurements. Use a measuring tape and measure multiple times to avoid making mistakes.

  3. When in doubt, ask a pro. Choosing the right size bathroom mirror isn’t always intuitive. If you’re investing in a large mirror and want to ensure it’s an investment well-spent, then consider working with a local bathroom mirror installer to achieve the perfect look and safely install the mirror. 

Factors that Influence Bathroom Mirror Size

Several factors influence the size of a bathroom mirror, including your personal style, budget, type of installation, lighting, and amount of upkeep. 

Aesthetic 

A mirror can serve as more than a practical solution—for some, mirrors strategically increase the aesthetic appeal of a bathroom. For example, you may want to consider whether you want an unframed or framed mirror. If you choose a frame, this can take up additional space.

Another example is deciding between one large mirror and two smaller mirrors. Two smaller mirrors have smaller widths but typically maintain a similar height to larger mirrors and are easier to install due to their lighter weight. 

Budget

Most mirror installations cost between $150 and $500. If your dimensions are unique and very specific to your bathroom’s size, then you may need to choose a custom-cut mirror. This option has a higher price tag—the cost to cut glass adds $50 to $75 to a standard-sized bathroom mirror. For larger mirrors, mirrors with unique beveling, or atypical shapes, you could spend over $200. You may prefer a standard bathroom mirror size to avoid these additional costs.

Installation Site

The size of your bathroom mirror is relative to the size of the space and where you’re installing it. Consider the size of your vanity or medicine cabinet and choose a mirror that matches the measurements that best suit your bathroom. 

Lighting

If you pick a mirror with built-in LED lighting around the frame, then you might not need to consider extra space, but if you plan on installing separate light fixtures above your mirrors, make sure that there is enough room to do so. An electrician near you can help you determine the amount of space needed to install lighting before you choose a bathroom mirror.

Maintenance

Larger mirrors require more physical labor and time to keep squeaky clean, especially if you choose a tall mirror. Even if you know how to clean a mirror without streaks, toothpaste, hard water, and other smudges can be a pain to remove regularly if your mirror is large. For a low-maintenance bathroom mirror, opt for one with smaller dimensions or less height. 

What to Do if You Have the Wrong Size Bathroom Mirror

The wrong bathroom mirror size won’t be the end of the world if it’s too small. You may struggle to see your full portrait or make do with lackluster visuals. But a bathroom mirror that is too large poses more serious problems. 

Glass that doesn’t quite fit onto a medicine cabinet can jut out and cause injuries. If your mirror is too large for your vanity, you might not be able to fit it in your bathroom at all. Since glass mirrors are heavy, it’s also important to factor in the location of your wall studs to ensure you can safely install them with the proper support. Failure to do so can result in the mirror falling and causing injury.

If you’re not confident about installing the right-sized bathroom mirror, contact a mirror installer near you for a professional opinion and high-quality installation.

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