Screen DPI Test
Estimate your screen's pixel density in PPI from its diagonal, and check the browser's nominal inch.
What is my screen resolution?
Your screen resolution appears below as soon as the page loads: in CSS pixels, the unit web pages use, and in physical pixels calculated from the pixel ratio. The readings update as you resize the window, zoom or rotate your phone.
Screen
—CSS px
≈ — physical px
Browser viewport
—CSS px
Device pixel ratio
—
Reading the screen size from your browser
- Aspect ratio
- —Worked out from the screen size, longer side first.
- Available screen area
- —Excludes space reserved by the taskbar, dock or menu bar, as reported by the browser.
- Orientation
- —
- Page zoom
- —In most desktop browsers, zoom and operating system scaling both change the pixel ratio; the page cannot tell them apart.
- Color depth
- —Bits per pixel as reported by the browser; most report 24 whatever the panel can do.
Screen resolution
The screen size is the resolution the operating system is using, in CSS pixels after any display scaling. On a scaled display it is smaller than the number of pixels the panel has.
Viewport
The viewport is the part of the browser window that shows the page, without tabs, toolbars or the window frame. Resizing the window or changing the zoom level changes it. Browsers differ in whether zoom also changes the screen size they report.
Physical pixels
The physical size shown here is the screen size multiplied by the device pixel ratio and rounded. It is calculated, not read from the display, so it can differ from the panel's native resolution when scaling and browser zoom are combined.
Runs entirely in your browser. Test results, audio and video never leave your device.
How to check your screen resolution
- Reset the browser zoom to 100 percent with Ctrl+0 (Cmd+0 on a Mac), so zoom does not change the numbers.
- Read Screen for your resolution in CSS pixels, and the ≈ physical px line under it for the same size in physical pixels. On Windows, the physical figure should match Display resolution in Settings.
- Read Browser viewport for the part of the window that shows the page, and Device pixel ratio for how many physical pixels wide each CSS pixel is.
- Check the Aspect ratio row, and Page zoom, which reads Looks like 125% (or similar) when the pixel ratio is not a whole number.
- Resize or move the window, or rotate your phone, and watch the values and the diagram follow.
- Press Copy details to copy the values, for example into a support request.
What is screen resolution?
Screen resolution is the number of pixels a display shows across and down, written as width ×height, such as 1920 ×1080. Browsers report it in CSS pixels, after the operating system's display scaling, so a scaled screen reads smaller than its native resolution. The viewport is usually smaller still: only the part of the browser window that shows the page.
Why your screen reads 1536 ×864 instead of 1920 ×1080
Display scaling. To keep text a comfortable size, the operating system scales everything up, so each CSS pixel covers more than one physical pixel, and web pages get the screen size in CSS pixels. Divide the native resolution by the scaling to get the size shown here, or multiply the size shown here by the device pixel ratio to get back to the native resolution. The figures assume browser zoom at 100 percent.
| Native resolution | Scaling | Screen shown here | Device pixel ratio |
|---|---|---|---|
| 1920 ×1080 | 125% | 1536 ×864 | 1.25× |
| 1920 ×1080 | 150% | 1280 ×720 | 1.5× |
| 2560 ×1440 | 125% | 2048 ×1152 | 1.25× |
| 2880 ×1800 | 150% | 1920 ×1200 | 1.5× |
| 3840 ×2160 | 150% | 2560 ×1440 | 1.5× |
| 3840 ×2160 | 200% | 1920 ×1080 | 2× |
Find your resolution in Windows, macOS, Android and iPhone
- Windows 11: Settings, then System, then Display. Display resolution lists physical pixels, with the native resolution marked Recommended, and Scale shows the scaling.
- macOS: Apple menu, then System Settings, then Displays. On a Retina screen the sizes offered there are scaled sizes, the same kind of number this page shows as Screen.
- Android: some phones offer a Screen resolution option under Settings, then Display. Otherwise the resolution is in the phone's specifications.
- iPhone and iPad: there is no resolution setting. The native resolution is in the model's technical specifications.
What this test can detect
- Your screen resolution in CSS pixels, and the physical resolution calculated from the pixel ratio.
- The browser viewport: the part of the window that shows the page, updated as you resize.
- Display scaling or browser zoom, shown by a pixel ratio such as 1.25× and the Page zoom hint.
- The screen's aspect ratio, such as 16:9, 16:10 or about 21:9.
- The available screen area without the taskbar, dock or menu bar, and the orientation.
- Where the window sits on the screen, drawn to scale in the diagram.
How it works
The page reads screen.width and screen.height for the screen, window.innerWidth and innerHeight for the viewport, and window.devicePixelRatio, along with the available area, orientation and color depth. The physical figure is the screen size multiplied by the pixel ratio and rounded.
The aspect ratio is reduced from the screen size, longer side first; within 1% of a common shape it reads about 16:9 or similar. A pixel ratio that is not a whole number gives the Looks like N% hint. Values update on resize and rotation, and are read again every second to catch a window moved to another monitor.
Limitations
- The physical figure is calculated, not read from the hardware. On a Mac set to a scaled resolution, it is the size macOS draws at, which can differ from the panel's native resolution.
- A web page cannot tell browser zoom from system scaling. In most desktop browsers both change the pixel ratio, so reset zoom before comparing with your settings.
- The viewport width includes the scrollbar where one takes up space, so the width a page can lay out in can be slightly smaller.
- Values describe the screen the window is on, and privacy settings in some browsers report a different size. Browsers do not report the screen's size in inches or its refresh rate: the Screen DPI Test works out pixel density from your screen diagonal, and the Refresh Rate Test estimates the rate from how often the browser draws.
Frequently asked questions
What does a device pixel ratio of 1.25 or 1.5 mean?
Each CSS pixel is drawn 1.25 or 1.5 physical pixels wide. On Windows it usually means display scaling at 125 or 150 percent; in most desktop browsers, page zoom changes it too. Ratios of 2 or more are normal on Retina Macs and phones.
What aspect ratio is my screen?
The Aspect ratio row names it. 1920 ×1080 and 2560 ×1440 are 16:9, 1920 ×1200 and 2560 ×1600 are 16:10, some laptops and tablets use 3:2, ultrawide monitors are about 21:9, and many phones are about 19.5:9.
Is my screen 4K?
Yes, if the ≈ physical px line under Screen reads 3840 ×2160 with browser zoom at 100 percent. Screen itself is in CSS pixels, so with scaling on, a 4K screen can read like 1440p or 1080p there. The line shows the resolution in use, so a 4K monitor set lower reads lower; on a Mac, check the display's specifications.
Why does my screen look blurry?
Often the resolution is set below the panel's native one, so the display scales the picture up and softens it. Choose the resolution Windows marks Recommended, or Default on a Mac. The grid in the Screen Geometry Test makes this softness easy to see.
Why is my screen resolution stuck at 1024 ×768 or 800 ×600?
Usually a missing or failed graphics driver. Without one, Windows uses a basic display driver that offers only a few resolutions. Install the driver from your PC or graphics card maker, then choose the Recommended resolution. A faulty cable, adapter or KVM switch can also hide the resolutions the monitor supports.
What size wallpaper fits my screen?
One at your physical resolution: the ≈ physical px line under Screen, read with browser zoom at 100 percent. A larger image with the same aspect ratio also fills the screen sharply.