Find your monitor size by measuring the screen diagonal

The size of a monitor is measured corner-to-corner across the screen itself, not including the frame or stand. You can find this measurement three ways: by checking the monitor's original documentation, by looking at the label on the back or bottom of the monitor, or by measuring the screen yourself with a tape measure or ruler.

Most people already know their monitor size from the box it came in or from a sticker on the back. If you've lost that information, a physical measurement takes about two minutes and requires only a ruler or measuring tape. Measure from the top-left corner of the screen to the bottom-right corner, staying on the glass or panel itself—do not include the plastic bezel around it.

Key Takeaways

  • Monitor size is always measured diagonally across the screen glass, from corner to corner, and is given in inches.
  • The quickest way to find your monitor size is to check the label on the back or bottom of the monitor itself.
  • If you measure by hand, use a ruler or tape measure and go from the top-left corner of the screen to the bottom-right corner, not including the plastic frame.
  • Common monitor sizes are 21.5, 24, 27, 32, and 34 inches, though many other sizes exist.
  • If you cannot find the size any other way, you can search your monitor's model number online to find the specifications.

Check the label on the back or bottom of your monitor

Most monitors have a label or sticker on the back panel or underneath the stand that lists the model number and screen size. This label is usually white or silver and contains small printed text. Look for a number followed by the word "inch" or the symbol "—for example, "24 inch" or "27".

If the label is hard to read or the text has faded, take a photo of it with your phone and zoom in on the image. The model number on this label is also useful: you can type it into a search engine along with the word "specifications" to find the exact screen size and other details about your monitor.

Measure the screen yourself with a ruler or tape measure

Place your ruler or tape measure at the top-left corner of the screen glass—the actual display surface, not the plastic frame around it. Stretch it diagonally to the bottom-right corner of the screen. Write down the measurement in inches. If you measure in centimeters, divide by 2.54 to convert to inches.

Monitors are always sold and labeled in inches, so your final answer should be in inches. If your measurement comes out to 21.5, 24, 27, 32, or 34 inches, you have found a standard size. If it falls between standard sizes—for example, 25 or 28 inches—your monitor may be an older model or a specialty size, and you should search the model number to confirm.

Look up your monitor model number online

If you cannot find a label or prefer not to measure, search for your monitor's model number. You can usually find this number on the back of the monitor, on the stand, or in your computer's display settings. On Windows, right-click the desktop, select "Display settings," scroll down, and click "Advanced display settings." On Mac, go to the Apple menu, select "System Settings," then "Displays," and look for the model name.

Once you have the model number, type it into Google or your search engine along with the word "specifications." The manufacturer's website or a retailer page will show you the exact screen size, along with other details like resolution and refresh rate. This method is especially useful if your monitor is very old or the label has worn away.

Understand the difference between screen size and resolution

Screen size (measured in inches) and resolution (measured in pixels) are two separate things. A 24-inch monitor might have a resolution of 1920 × 1080 pixels, while another 24-inch monitor might have 2560 × 1440 pixels. Both are 24 inches across the diagonal, but the second one packs more pixels into the same space, making text and images sharper.

When someone asks "what size is your monitor," they are asking for the diagonal measurement in inches, not the resolution. However, both numbers are useful to know if you are shopping for a replacement or troubleshooting display problems. You can find both on the label, in your computer's display settings, or on the manufacturer's website.

Common monitor sizes and what they are used for

Most desktop monitors fall into a few standard sizes. A 21.5-inch or 24-inch monitor is common for office work, web browsing, and everyday computing. A 27-inch monitor is popular for photo and video editing, gaming, and programming because it offers more screen space without requiring you to move your eyes as much. A 32-inch monitor is less common for desktop use but appears in professional studios and some gaming setups.

Ultrawide monitors (such as 34 inches) are measured the same way—corner to corner—but have a wider aspect ratio than standard monitors, giving you more horizontal space. Older monitors might be 19 inches or 20 inches, and you may still find these in offices or schools. The size you need depends on how far you sit from the screen and what you use it for, but knowing your current size is the first step.

Frequently Asked Questions

Does monitor size include the plastic frame around the screen?

No. Measure only the glass or panel itself, from corner to corner. The plastic bezel (frame) around the screen is not part of the measurement. This is why two monitors of the same size can look slightly different in overall width and height—the bezel thickness varies by brand and model.

What if my measurement doesn't match any standard size?

If you measure 23 inches or 25 inches instead of a standard 24, you likely have an older monitor or a specialty model. Search the model number online to confirm the exact size. Manufacturers sometimes round or use slightly different measurements in different regions, so the label may say 24 inches even if your ruler shows 23.5.

Can I find my monitor size in Windows or Mac settings?

The display settings show resolution and refresh rate, but usually not the physical screen size in inches. However, they do show the monitor model name, which you can search online to find the size. This is faster than measuring if you are comfortable using your computer's settings menu.

Why do monitors get smaller when I buy a new one with the same size number?

You are likely comparing the screen size to the overall footprint of the monitor. Newer monitors have thinner bezels, so a 27-inch monitor today has a smaller frame than a 27-inch monitor from ten years ago, even though the screen itself is the same size. The diagonal measurement of the glass has not changed.

Is there a difference between monitor size and screen size?

No, these terms mean the same thing. Both refer to the diagonal measurement of the display in inches. You may also hear "display size" used the same way. All three terms describe the corner-to-corner measurement of the screen glass.