Screen Resolution Size Detector

Instantly check screen resolution, viewport size, device info and test responsive layouts with one click.

See your real screen resolution in one click, then test your site on phones, tablets and desktop sizes, and measure anything on the page. Screen Resolution Size Detector is a fast, simple tool for developers, designers, QA testers and everyday users. No more opening DevTools or visiting a website just to check your resolution. Click the icon (or press Alt+Shift+S) and everything appears in one clean popup. ━━━━━━━━━━━━━━━━━━━━ WHAT'S NEW IN VERSION 1.1 ━━━━━━━━━━━━━━━━━━━━ ✔ Real resolution, now correct even with display scaling (for example 1920 × 1080 on a laptop set to 125%) ✔ Aspect ratio shown as 16:9, 16:10, 21:9 and more ✔ 8 phone and tablet previews (was 2), with a Rotate button for landscape ✔ Custom size: type any width and height ✔ Measure tool: hover any element to see its size, or drag to measure any area ✔ One-click screenshot of the visible page ✔ Copy buttons and "Copy All" ✔ Keyboard shortcut: Alt+Shift+S ✔ More accurate browser and operating system detection ✔ Works on more pages, including new tabs and browser pages ✔ Many bug fixes ━━━━━━━━━━━━━━━━━━━━ SCREEN & DEVICE INFO ━━━━━━━━━━━━━━━━━━━━ ✔ Screen resolution: your true physical pixels ✔ Scaled resolution: the size websites see after display scaling ✔ Aspect ratio ✔ Viewport size: the actual visible page area ✔ Device pixel ratio (DPR) ✔ Orientation (portrait or landscape) ✔ Color depth ✔ Browser and OS, in plain words (for example "Chrome 141 — Windows 11 (x86 64-bit)") ✔ Platform and language Copy any value with one click, or use "Copy All" to paste every detail into a bug report or support ticket. ━━━━━━━━━━━━━━━━━━━━ RESPONSIVE TESTING ━━━━━━━━━━━━━━━━━━━━ DESKTOP SIZES Four common laptop and desktop sizes, from 1280 to 1920 pixels wide. Each one resizes your browser window so the page area matches the size exactly. If your screen is too small for a size, the extension tells you. PHONE & TABLET PREVIEW Choose from eight popular phone and tablet screen sizes. Your current page opens inside a device frame on top of the page, so your window stays the same size. • Rotate between portrait and landscape without reloading • Scales automatically to fit your window • Close with ✕, the Esc key, or by clicking outside CUSTOM SIZE Type any width and height. Sizes under 600 px wide open as a device preview. BACK TO NORMAL VIEW One click closes any preview or tool and restores your window. ━━━━━━━━━━━━━━━━━━━━ TOOLS ━━━━━━━━━━━━━━━━━━━━ 📐 MEASURE Hover over any element to see its exact width and height. Click and drag to measure any area in pixels, such as gaps, images or columns. Links and buttons won't trigger while you measure. Press Esc to exit. 📷 SCREENSHOT Save the visible part of the page as a PNG, named with its size and the time. ━━━━━━━━━━━━━━━━━━━━ WHO IT'S FOR ━━━━━━━━━━━━━━━━━━━━ ✔ Web developers checking breakpoints ✔ Designers testing responsive layouts ✔ QA testers doing multi-device checks ✔ Anyone who wants to know their real screen resolution ━━━━━━━━━━━━━━━━━━━━ PRIVACY & PERMISSIONS ━━━━━━━━━━━━━━━━━━━━ This extension does not collect, store or send any of your data. Everything runs locally in your browser. Permissions and why they're needed: • activeTab and scripting: read the screen and viewport size from the current page, and show the device preview and measure tool on it. Nothing on the page is changed permanently; closing a tool removes it. • tabs: find the current tab and window to measure and resize them. • Access to websites: lets the Refresh button and tools keep working after you move to another page, without clicking the icon again. When you first install the extension, and after each update, it opens a page on whatismyscreenresolution.info. ━━━━━━━━━━━━━━━━━━━━ MORE FREE TOOLS ━━━━━━━━━━━━━━━━━━━━ Our website, https://whatismyscreenresolution.info, has more free tools for checking screens and testing responsive layouts. The popup links to them at the bottom. ━━━━━━━━━━━━━━━━━━━━ FEEDBACK ━━━━━━━━━━━━━━━━━━━━ Missing a device or found a bug? Leave a review or send a suggestion. We update device presets and detection regularly.