screen info

Display and device diagnostics

Screen resolution, viewport, device pixel ratio, refresh rate, browser capabilities, WebGL info, fullscreen and dead pixel tests. Everything is read locally in your browser.

Fullscreen test

Enter fullscreen to see the exact usable display dimensions your browser reports. Press Escape at any time to exit.

Dead pixel test

Look for pixels that remain a different color from the rest of the screen. Tap or press the arrow keys to cycle through solid colors. Press Escape or the Close button to exit at any time.

This does not enter fullscreen automatically. Use the Fullscreen Test first if you want to check the entire panel.

Explanations

Screen resolution vs viewport
Screen resolution is the total pixel grid of your monitor or phone. The browser viewport is the drawable area inside your window; it excludes the address bar, the OS taskbar, and any docked panels. On a maximized desktop window the two are close but rarely identical.
What device pixel ratio means
Device pixel ratio (DPR) is the number of physical pixels that make up one CSS pixel. A DPR of 2 means each CSS pixel is drawn as a 2 x 2 block of physical pixels; a 1280 CSS-pixel wide viewport occupies 2560 physical pixels on the panel. Retina and most modern phone screens report a DPR of 2 or 3.
Why your viewport is smaller than your screen
Even when a browser is full width, the OS taskbar, browser chrome, and any dev tools panel reduce the viewport. On phones the address bar also shrinks and grows as you scroll.
Refresh rate, color depth, WebGL
Refresh rate is how many times per second the panel can redraw. Color depth is the number of bits used to store each pixel color (24 or 32 bit is standard). WebGL is the browser interface to your graphics processor; the vendor and renderer strings tell you what the driver wants to identify as, not necessarily the exact hardware.
How to test for dead pixels
A dead pixel is a pixel that stays off (looks black) or stuck on a single color across every scene. Fill the screen with solid colors in turn (black, white, red, green, blue, gray) and look for pixels that stand out from the field.
Why some hardware information is hidden
Browsers deliberately withhold precise hardware details (exact GPU model, exact monitor model, serial numbers) to reduce fingerprinting. This tool respects those limits; nothing here bypasses them.

Device information is read locally in your browser. Nothing is uploaded.

AIExplain my display

Frequently asked

What is my screen resolution?
Screen resolution is the total pixel grid of your display. The tool reads it from window.screen.width and window.screen.height and shows the values in the Display section at the top of the page.
Why is my viewport smaller than my screen resolution?
Viewport is the drawable area inside the browser window. It excludes the OS taskbar, browser chrome, docked dev tools, and (on phones) the address bar. Even a maximized browser rarely uses every physical pixel.
What does device pixel ratio mean?
Device pixel ratio (DPR) is the number of physical pixels that make up one CSS pixel. A DPR of 2 means every CSS pixel is drawn as a 2 by 2 block of physical pixels, which is why a Retina-class screen looks sharper at the same CSS size.
Can a website detect my monitor refresh rate?
Not exactly. The tool estimates the refresh rate by sampling requestAnimationFrame intervals for a short window, then snaps the result to a common rate (60, 90, 120, 144, 165, 240) when it is within 5 percent. The value is an estimate, not hardware telemetry.
Can a website detect my GPU?
Browsers expose the WebGL renderer and vendor strings, but many browsers deliberately hide the exact GPU model for privacy. The Display Graphics section shows whatever the browser reveals; nothing here bypasses those protections.
How do I test for dead pixels?
Open the Dead Pixel Test on this page and cycle through the solid colors (black, white, red, green, blue, gray). A dead pixel is a pixel that stays a different color from the rest of the field. Use the Fullscreen Test first if you want to check the entire panel.
Does this tool upload my device information?
No. Every value on the page is read from local browser APIs and stays in your browser. Analytics only records anonymous section-open and test-started events; the exact resolution, GPU renderer, capability set, and user agent are never sent.