Resolution Test
Check your current screen resolution, browser viewport, DPR, and display details instantly.
Values are reported by your browser. Browser zoom and operating-system scaling can affect them. Estimated display pixels do not guarantee native panel resolution.
How to check screen resolution
Screen resolution is the width and height a browser reports for the display in CSS pixels. The viewport is the page area left after browser controls, sidebars, scrollbars, and mobile interface areas are excluded. They answer different questions: screen size describes the reported display boundary, while viewport describes the current page workspace. A 1920 x 1080 screen can have a smaller viewport when the window is not maximized. Record both values when diagnosing layout behavior.
Device pixel ratio, or DPR, describes the relationship between CSS pixels and device pixels. A DPR of two maps one CSS pixel to two device pixels in each direction. It helps explain breakpoints, image density, and visual tests, but does not prove a physical panel specification. Estimated pixels are calculated from browser-reported CSS dimensions and DPR. Treat them as an estimate because browser zoom and operating-system scaling can change the reported relationship without changing the physical panel.
How to read the live result
- Record screen and viewport size together, plus whether the window is maximized. This separates the reported display boundary from the page workspace during a layout investigation.
- Check DPR and aspect ratio for density and shape. They explain rendering context, but neither identifies the panel model or proves its native mode.
- Use available area and outer window size to explain lost workspace. Recheck them after moving the window or changing system UI settings.
- Compare orientation and color depth for device or screenshot tests. Record browser, OS scale, and app so another person can reproduce the session.
Troubleshoot blurry or unexpected results
If text looks soft, reset browser zoom to 100 percent, check operating-system scaling, and compare another browser. For a monitor test, compare the OS native or recommended mode with browser values, then move the window to each display and record the active monitor. Zoom, scaling, window chrome, and rendering change page coordinates, so browser measurements can differ from hardware specifications. This checker reports observable values; it does not determine a panel's native mode.
Common resolution reference
| Format | Typical use |
|---|---|
| 1280 x 720 | HD video and compact laptops |
| 1920 x 1080 | Full HD monitors and video |
| 2560 x 1440 | High-density desktop work |
| 3840 x 2160 | 4K media and large displays |
These formats are reference labels, not a hardware diagnosis. HD, Full HD, QHD, and 4K describe common dimensions for video, laptops, desktop work, and large displays. Use this session's live result, compare the OS display mode separately, and use the standard resolution chart for a broader list.
Developer and QA uses
Developers can record viewport, DPR, aspect ratio, and orientation with a bug report. QA should also capture browser zoom, operating-system scaling, window state, active monitor, color depth, and the test path. Reproduce the breakpoint at a known viewport width, compare phone and laptop sessions, verify screenshot targets, and confirm that the layout changes at the expected width. These measurements make a report repeatable without treating browser output as hardware diagnosis. For fixed-size simulations, use the responsive design testerinstead.
Common Resolution Test Questions
Why is my browser viewport smaller than my screen resolution?
Browser controls, sidebars, scrollbars, and mobile interface areas reduce the space available to a web page. A windowed desktop browser may also leave part of the screen outside the page. This is expected and does not mean the display has lost pixels. Distinguish a smaller browser window from a smaller physical display; viewport size is the relevant number for layout and breakpoint debugging.
Does DPR reveal my native panel resolution?
No. DPR is a browser-reported relationship between CSS and device pixels. Zoom, operating-system scaling, browser configuration, and display hardware can affect it, so DPR does not guarantee native panel resolution. Use DPR as context for screenshot scaling and sharpness, then verify the CSS viewport separately. Check the operating system or manufacturer documentation for hardware specifications.
What does orientation mean?
Orientation labels the reported screen as landscape, portrait, or square by comparing width and height. It describes current geometry, which may change after rotating a device or moving a browser window; it does not identify a monitor model. Square means the reported width and height are equal. Zoom can affect related measurements without changing device orientation.
What is available area?
Available area is the browser-reported screen space remaining around system UI. Taskbars, docks, and mobile controls can reduce it, and the value may differ by monitor. Use it to explain workspace constraints or clipping near a taskbar or toolbar, not to infer panel size. Do not add it to screen width to estimate hardware specifications.
Can I share these results?
On supported mobile devices, the Share button uses native sharing. On desktop, when sharing is unavailable, or when native sharing fails, it copies the canonical checker URL. The link does not include a hardware diagnosis, so add the recorded values, browser zoom, operating-system scale, and active display to a bug report. Recipients can open the same checker page; mention whether the session used one or multiple monitors.
Do values update when I resize?
Yes. Values refresh after a resize or orientation change, and moving the window between displays may change them. Reload after changing a browser or operating-system setting, then capture a fresh result with the test conditions. A resize event reflects the current session, not a history of display states.