Screen Size Checker
Check your screen size, resolution, viewport dimensions, and device pixel ratio instantly in your browser.
How does this test work?
A screen size checker reads your display dimensions from the browser. It shows your screen resolution, viewport size, device pixel ratio, and estimated physical screen size without installing software.
How to use the Screen Size Checker
Open the Screen Size Checker on any device with a modern browser — desktop, laptop, tablet, or phone. No downloads, plugins, or signup required. The tool loads instantly and works in Chrome, Firefox, Safari, Edge, and other Chromium-based browsers.
Follow the on-screen instructions to run the test. Results are displayed immediately in your browser. You can repeat the test as many times as needed. For the most accurate results, close other tabs and applications to reduce interference.
Privacy: This test runs entirely in your browser using standard web APIs. No data is collected, uploaded, or stored on any server. Camera, microphone, keyboard, mouse, and controller inputs are processed locally and never leave your device. DeviceKit does not use analytics cookies or tracking scripts.
Browser note: Some hardware values are estimated because browsers limit direct access to device hardware for security and privacy reasons. Results may vary slightly between browsers and operating systems. For the most reliable measurements, use an up-to-date version of Chrome or Edge on a desktop computer.
Frequently Asked Questions
What is the difference between screen resolution and viewport size?+
Screen resolution is the total pixel count of your display. Viewport size is the visible area inside your browser window, which is smaller due to browser chrome (toolbars, tabs).
Why does my screen show a different resolution than advertised?+
Display scaling (125%, 150%, etc.) makes the effective CSS resolution lower than the physical resolution. Check device pixel ratio to see the scaling factor.
Related Tests
Screen Resolution
Instantly check your screen resolution, viewport size, device pixel ratio, and estimated DPI. Works on monitors, laptops, phones, and tablets.
Refresh Rate Test
Measure your display's refresh rate in Hz using your browser. Check if your monitor is running at 60Hz, 120Hz, 144Hz, 240Hz, or higher.