What Is My Screen Resolution?
See your screen resolution, window size, device pixel ratio, and aspect ratio — instantly, with nothing uploaded.
Screen pixels vs. window pixels vs. physical pixels
Screen resolution is your entire display as the browser sees it — the taskbar, dock, and browser chrome included. Window size (the viewport) is only the portion of the screen your browser hands to the web page, inside tabs and toolbars, so it is always smaller and changes when you resize the window.
Browsers measure both in CSS pixels, which are not always the monitor's raw dots. Your operating system's display scaling (125%, 150%, 200%…) and the screen's pixel density set the device pixel ratio — how many physical pixels draw one CSS pixel. Multiply the screen size by the DPR to get the true physical pixel count: a 4K panel at 200% scaling reports 1920 × 1080 with a DPR of 2. Browser zoom shifts the CSS numbers the same way, which is why resetting zoom to 100% (Ctrl/Cmd + 0) shows the unscaled value.
Common screen resolutions
| Resolution | Name | Aspect ratio | Typical devices |
|---|---|---|---|
| 1920 × 1080 | Full HD (1080p) | 16:9 | Most common desktop monitor |
| 1366 × 768 | HD (720p-class) | ≈16:9 | Older and budget laptops |
| 2560 × 1440 | QHD (1440p) | 16:9 | Gaming and productivity monitors |
| 3840 × 2160 | 4K UHD | 16:9 | 4K monitors and TVs (often 150–200% scaled) |
| 360 × 800 | Android viewport | 9:20 | Common Android phones (CSS pixels, DPR 2–3) |
| 390 × 844 | iPhone viewport | ≈9:19.5 | iPhone 12/13/14 (CSS pixels, DPR 3) |
Quick Answer
Your screen resolution is the number of pixels your display shows, measured as width × height — for example 1920×1080. This free tool reads it directly from your browser and also shows your current window size, device pixel ratio (DPR), effective physical pixel count, color depth, and aspect ratio. Everything is calculated locally on your device: nothing is uploaded, no sign-up, and values update live as you resize the window or rotate a tablet or phone.
How It Works
Open this page in any browser on the device you want to check
Read your screen resolution and browser window size instantly at the top
Check the device pixel ratio and the effective physical pixel resolution (screen size × DPR)
Resize the browser window or rotate your device — values update live
Compare your resolution against the common resolutions table below
Key Facts
- Shows your screen resolution (screen.width × screen.height) instantly
- Live browser window size that updates as you resize the window
- Device pixel ratio (DPR) with effective physical pixel resolution (screen size × DPR)
- Color depth in bits per pixel reported by your display
- Aspect ratio reduced to its simplest fraction (e.g. 16:9, 16:10)
- Detects landscape or portrait orientation, including device rotation
- 100% client-side: no data leaves your browser, nothing is stored
- Free to use, no sign-up, works on desktop, tablet, and mobile
Frequently Asked Questions
Why does my browser report a different resolution than my display settings?
Browser zoom and the operating system's display scaling change the numbers a browser reports. If your OS scaling is set to 125% or 150%, or your browser zoom is above 100%, screen.width and screen.height are reported in CSS pixels, which are smaller than the display's raw pixel grid. Multiply the reported screen size by the device pixel ratio (DPR) to get the true physical pixel resolution. For example, a 4K panel (3840×2160) at 200% scaling reports 1920×1080 with a DPR of 2.
What is device pixel ratio (DPR)?
Device pixel ratio is the number of physical hardware pixels used to draw one CSS pixel. A standard monitor has a DPR of 1: one CSS pixel equals one physical pixel. Retina and other high-DPI screens typically have a DPR of 2 or more, so a "1920×1080" Retina-style display actually packs 3840×2160 physical pixels. DPR exists so text and UI stay the same physical size on sharper screens while looking far crisper.
What is the difference between screen resolution and window size?
Screen resolution is your entire display — every pixel the monitor can show, including the taskbar, dock, and browser chrome. Window size (the viewport) is only the part of the screen your browser gives to the web page, inside toolbars and tabs. That is why window.innerWidth/innerHeight is always smaller than the screen size, and why it changes every time you resize or maximize the browser window.
Why does my screen resolution change when I zoom the browser?
Zooming does not change your monitor — it changes how many CSS pixels fit. At 110% zoom each CSS pixel occupies more physical space, so fewer of them fit on screen and the reported resolution appears to shrink. Set the zoom back to 100% (Ctrl/Cmd + 0) to see your display's unscaled CSS resolution, then multiply by the DPR for the physical pixel count.
What do the common resolutions like 1920×1080 and 1366×768 mean?
These are width × height counts in pixels. 1920×1080 (Full HD, 16:9) is the most common desktop resolution. 1366×768 is typical of older and budget laptops. 2560×1440 (QHD) and 3840×2160 (4K UHD) are sharper step-ups. On mobile, 360×800 and 390×844 are common CSS-pixel viewports for Android and iPhone respectively — the underlying panels usually have a higher physical pixel count via a DPR of 2 to 3.
Is this screen resolution test private?
Yes. The tool reads your display information using standard browser APIs (screen, window.innerWidth, devicePixelRatio) entirely on your own device. No data is sent to any server, nothing is logged or stored, and there is no sign-up. Close the tab and nothing remains.