What Is My Screen Resolution?
Your display and browser details, detected right now.
What do these numbers mean?
- Screen resolution is the size of your display in CSS pixels as reported by the browser.
- Pixel ratio shows how many physical pixels make one CSS pixel; 2 or more means a high-density (Retina) screen.
- Physical pixels is resolution multiplied by pixel ratio — roughly your display’s true pixel count.
- Browser window is the visible page area and changes as you resize the window.
FAQ
Why is my resolution different from what I set?
Operating systems scale the display. A 4K screen scaled to 150% reports 2560×1440 here with a pixel ratio of 1.5.
Is this data sent anywhere?
No. It is read in your browser and shown only to you.
Reading the results
- Open the page and the four headline figures fill in straight away: screen resolution, browser window, pixel ratio and physical pixels. Nothing needs to be typed or clicked.
- Scroll to the table underneath for the longer list: available screen, inner and outer window size, colour depth, orientation, touch points, CPU cores, language, time zone, online status and the raw user agent string.
- Resize the window, change the browser zoom or rotate a tablet and the numbers refresh. The page listens for the browser's resize event and rebuilds the table each time.
- Press Copy details to put every row on your clipboard as plain "label: value" lines. That is handy when you are filing a bug report or asking a web designer why a layout looks wrong on your machine.
Where each number comes from
Everything shown here is read from standard browser objects, with no measurement or guessing by the page itself. The screen size comes from screen.width and screen.height. The "available screen" row uses screen.availWidth and availHeight, which is the same area minus permanent interface such as a taskbar or dock, so it is often a little shorter than the full screen.
The two window rows are different measurements. "Inner" is the page viewport, the area your website actually draws into, and it is the size that CSS media queries react to. "Outer" includes the browser's own frame, tabs and address bar, so it is always at least as large as the inner size.
The pixel ratio is devicePixelRatio. The "physical pixels" tile simply multiplies the reported screen width and height by that ratio and rounds the result. It is an estimate of the hardware grid, and the browser is not telling you the panel's native resolution directly.
A worked example
Suppose a laptop has a 3840 × 2160 panel and the operating system is set to 200% scaling. The browser reports a screen of 1920 × 1080 and a pixel ratio of 2. The page multiplies 1920 × 1080 by 2 and shows 3840 × 2160 as the physical pixels, which matches the panel. If you then pick 150% scaling instead, the screen row becomes 2560 × 1440, the ratio becomes 1.5 and the physical figure is again 3840 × 2160. The CSS size changed while the hardware stayed the same.
Zooming a desktop browser page also changes the numbers. Pressing zoom in typically makes the pixel ratio climb and the inner window size shrink, because each CSS pixel now covers more physical pixels. Zoom the page back to 100% before you read the screen figures if you want the unscaled values.
Common uses
- Designing and testing: check the viewport size your visitors really get, rather than the monitor's marketing resolution, before choosing breakpoints.
- Image sizes: if you export a wallpaper or a banner, the physical pixel figure tells you whether a sharp image needs to be larger than the CSS size. A ratio of 2 means an image shown at 400 CSS pixels wide needs about 800 pixels to look crisp.
- Support requests: copy the details and paste them into an email so the person helping you sees the browser, language and time zone without asking.
- Checking a second device: open the page on a phone or tablet to see its CSS resolution and whether the touch points row reports touch support.
Tips and limits
- The values describe what the browser reports, and that is sometimes not the whole truth. Privacy-focused browsers can round or hide some details, and virtual machines or remote desktop sessions report their own virtual screen.
- With several monitors, the figure normally reflects the display that the browser window is currently on. Drag the window to another monitor and reload to compare.
- On phones, the reported width is in CSS pixels, so a modern handset often shows a number far smaller than its marketing resolution. That is normal.
- CPU cores is the logical processor count the browser exposes. It can differ from the number of physical cores, and "unknown" appears when the browser does not provide it.
- The user agent line is only a self-description sent by the browser. Do not treat it as proof of the real device or version.
More questions
Why do the screen and window sizes not match when my browser is maximised?
A maximised window still has browser chrome and, on many systems, a taskbar. The outer size includes the frame, while the inner size covers only the page area, so both are smaller than the full screen row.
Why is my pixel ratio a decimal like 1.25?
That comes from fractional display scaling (125%) or from browser zoom. Ratios such as 1.25, 1.5 and 1.75 are common on Windows laptops, while 2 and 3 are typical for Retina and phone screens.
Can I use this to find out my monitor's refresh rate or size in inches?
No. Browsers do not report refresh rate or physical size, and this page shows only fields the browser exposes. Check your display settings or the manufacturer's specifications for those.