The simplest way to measure your monitor

The size of your monitor is the diagonal distance across the screen, measured in inches from one corner to the opposite corner. You can find this number three ways: check the original box or manual, look at your computer's display settings, or measure the screen yourself with a tape measure.

If you still have the box your monitor came in, the size is printed on the outside — usually on the front or back in large text, often followed by "inch" or a quotation mark symbol ("). This is the fastest way to know for certain.

If the box is gone, your operating system can tell you. On Windows, right-click the desktop, select "Display settings," scroll down, and look for "Display resolution" — the size may appear there, though not always. On Mac, click the Apple menu, choose "System Settings," then "Displays," and the size usually appears in the resolution information.

Key Takeaways

  • Monitor size is the diagonal measurement across the screen in inches, not the width or height alone.
  • The original box or manual is the most reliable place to find the exact size if you still have it.
  • Windows and Mac both display monitor size in their settings, though the location and clarity vary by version.
  • If you measure by hand, measure from the inside edge of the frame (not including the plastic border) diagonally corner to corner.
  • Common monitor sizes are 21, 24, 27, 32, and 34 inches — knowing yours helps when shopping for a replacement or stand.

Finding the size in Windows settings

Windows stores monitor information in a few places. The most direct route is to right-click your desktop, select "Display settings," and scroll to the bottom of the window. Look for a section labeled "Advanced display settings" or "Display information." Some Windows versions show the monitor model name and size here; others show only resolution.

If the settings don't list the size, try the Device Manager. Press Windows key + X, select "Device Manager," expand "Monitors," right-click your monitor name, choose "Properties," and click the "Driver" tab. The monitor model is listed here — you can then search that model number online to find its size.

A third option is to check what Windows knows about your hardware. Press Windows key + Pause/Break to open System Information, or search "System Information" in the Start menu. This shows your graphics card and sometimes monitor details, though not always the screen size directly.

Finding the size on a Mac

On a Mac, click the Apple menu in the top left, then "System Settings" (or "System Preferences" on older versions). Navigate to "Displays" and look at the resolution information — some Mac models show the screen size here, while others show only the resolution in pixels.

If the size isn't listed in Displays, try "About This Mac" from the Apple menu. Click "System Report" and look for "Graphics/Displays." The monitor model name may appear here. You can then search that model online to find its diagonal measurement.

For external monitors connected to a Mac, the information is less reliable in the system settings. Your best bet is to check the monitor's own menu — most external monitors have a button on the back or bottom that opens an on-screen display showing the model number.

Measuring your monitor by hand

If you want to verify the size or the settings don't show it, a tape measure works. Lay the tape measure diagonally from the top-left corner of the screen to the bottom-right corner, measuring only the glass or display surface itself — not the plastic frame or bezel around it. Round to the nearest inch.

Be careful to measure the actual screen area. Many monitors have a thick plastic border, and including that border will give you a larger number than the official size. The official measurement counts only the lit display area.

If your monitor is mounted on an arm or stand, you may need to angle it slightly to get the tape measure across the diagonal. A straight diagonal line from corner to corner is what matters, not the path the tape takes around the frame.

Why the size matters

Knowing your monitor size helps when you're shopping for a replacement, buying a new stand, or choosing a monitor arm. It also matters if you're troubleshooting display problems — support pages often ask for your screen size to narrow down the issue.

Monitor size also affects how much screen space you have for work. A 24-inch monitor is common for office work and fits most desks. A 27-inch monitor gives noticeably more room without taking up much extra space. Anything larger than 32 inches starts to require you to move your head to see the corners, which is why ultrawide monitors (34 inches and wider) are designed differently — they're wider than they are tall.

Common monitor sizes and what they look like

Most monitors sold today fall into a few standard sizes. A 21-inch monitor is small and compact, often found in older offices or as a secondary screen. A 24-inch monitor is the current standard for most work and gaming — it fits a typical desk and provides enough space without being overwhelming.

A 27-inch monitor is noticeably larger and popular for photo editing, video work, and gaming. A 32-inch monitor is large enough that you'll notice the difference in how much you can see at once, though it requires more desk space. Ultrawide monitors start at 34 inches and stretch horizontally — these are measured diagonally like any other monitor, but they feel much wider than a standard 27-inch screen because they're shaped differently.

What to do if you can't find the size

If your monitor doesn't have a visible label and the settings don't show the size, look for the model number on the back or bottom of the monitor. Most monitors have a sticker or label with the brand name and model number printed on it. Take a photo of this label and search the model number online — the manufacturer's website or a retailer's product page will list the diagonal size.

If there's no label visible, the monitor may be very old or custom-built. In that case, measuring by hand is your most reliable option. Measure the diagonal as described above, and round to the nearest inch — you'll get a number close enough to identify the monitor's original size.

Frequently Asked Questions

Is the monitor size the same as the width or height?

No. Monitor size is always the diagonal measurement, not the width or height. A 24-inch monitor is 24 inches from corner to corner diagonally, but it's roughly 21 inches wide and 12 inches tall. This is why two monitors with the same diagonal size can look different if they have different aspect ratios — one might be wider and shorter, the other taller and narrower.

Does the plastic frame around the screen count toward the size?

No. The official size counts only the lit display area, not the plastic bezel or frame. When you measure by hand, measure from the inside edge of the frame where the screen actually begins, not from the outer edge of the plastic border.

Can I find the monitor size if I only know the resolution?

Not reliably. Resolution (like 1920 × 1080) tells you how many pixels fit on the screen, but the same resolution can be on monitors of different sizes. A 24-inch and a 27-inch monitor can both have 1920 × 1080 resolution — the pixels are just larger on the bigger screen. You need the actual model number or a direct measurement to know the size.

What if my monitor is built into my laptop?

Laptop screen sizes are listed in the original box or manual, or in the laptop's system settings under "Displays." Common laptop sizes are 13, 14, 15, and 17 inches. You can also search your laptop's model number online — the screen size is always listed in the full specifications.

Does a curved monitor measure differently?

No. Curved monitors are measured the same way — diagonally from corner to corner of the display area, not along the curve. The curve doesn't change the official size, only how the screen is shaped.