What screen details can a browser actually enumerate?

You may want to know whether your browser can see both monitors, which resolution each one uses, or how Windows is scaling the desktop. A browser can report some useful screen details, but it does not have unrestricted access to every specification stored by your monitor or graphics hardware.

The Screens tool lists the displays the browser can detect, with resolution and scale information, and lets you run a color test on a selected screen. Here is how to read that information and what to check if a display is missing.

Check the screens your browser can see

1. Open Screens on the computer connected to the displays you want to check. A browser can only report screens available to that device and browser session.
2. Look through the detected display list. Compare the number of entries with the screens connected and enabled in your operating system.
3. Check each display's resolution and scale information. These values can help you spot a screen running at an unexpected size or scaling level.
4. Choose a screen for the color test if you want to check its visible colors. This checks what appears on the display, not its exact color accuracy or internal hardware.

For a separate check of a single display's colors and refresh rate, open the Display Test. The two tools answer different questions: Screens helps you inspect detected displays and their reported dimensions, while Display Test checks visible display behavior.

What the result means

Every connected screen appears

The browser can access a listing for each screen in this session. The reported resolution and scale are useful for checking your current desktop setup, but they are not a complete inventory of monitor hardware. They do not confirm the screen's model, serial number, cable type, or measured color accuracy.

Only one screen appears

This does not automatically mean the second monitor is broken. The operating system may not have enabled it, or the browser may not support or have permission to use the available multi-screen information. Compare the tool with your operating system's display settings before changing cables.

The resolution or scale looks different from what you expect

Resolution and scale describe related but different things. Resolution is the number of pixels used for the display image. Scale changes the size of text and interface elements, so a desktop can look larger or smaller without changing the monitor's physical pixel count. Browser values can also be presented differently from the labels in system settings, so compare the values in the same place before deciding they disagree.

The list does not show a detail you need

A website cannot simply inspect every setting in a graphics driver or read every piece of monitor identification data. Browsers limit access to device information for privacy and security. A missing model name, serial number, HDR setting, or physical size is not proof that the screen lacks that feature.

What to check if a screen is missing

1. Confirm the operating system sees it. On Windows 11, open Settings › System › Display and check whether both displays appear. On macOS, open System Settings › Displays. If the operating system lists only one, the browser cannot report the other one.
2. Check the display connection. Make sure the monitor is powered on and set to the correct input. Reseat the cable at both ends, or try another port or cable if available. For a dock or adapter, check that it supports the number of displays and resolutions you are using.
3. Enable the second display. In Windows 11, open Settings › System › Display, select the display and check the multiple-display option. On macOS, use System Settings › Displays to review the detected display arrangement and settings.
4. Check browser access. If the browser asks for permission to access information about multiple screens, allow it only if you are comfortable doing so. If no permission prompt appears or the browser lists only the current screen, try a recent version of a browser with multi-screen support.
5. Reload the tool after changing the setup. Connect or enable the displays first, then reload the page. A browser page may not update its screen list immediately after you change a cable, dock, or display setting.
6. Compare the reported resolution with system settings. Use the operating system's display settings as the reference for the active desktop resolution and scaling. If both places show the same display in different units or formats, that difference alone does not indicate a fault.

What a browser cannot prove

A browser screen list is a view of information the operating system and browser make available to the page. It is not a hardware diagnostic report. It cannot establish that a monitor is connected directly rather than through a dock, identify a failing cable, or verify the panel's true color performance.

Some multi-screen information depends on browser support and permission. If the list differs between browsers, that can point to a browser limitation rather than a change in the monitor setup. The Screens tool can still help you check the displays it can access, but use your system's display settings for the full desktop arrangement.

If the operating system also fails to detect a monitor, test another cable or port and check the monitor's input selection before considering a repair.