Screen Resolution Checker
Live display and capability report: screen + viewport size, device pixel ratio, aspect ratio (with the closest common match), color depth, gamut, dynamic range, refresh rate (measured), GPU vendor/renderer, WebGL2 + WebGPU support, CPU cores, RAM, network speed, AVIF/WebP/AV1 codec support, Tailwind & Bootstrap breakpoint matcher and more.
Reading display info…
All values are read from your browser locally. Nothing is sent to a server.
How to use this screen resolution checker
- Open the page on the device you want to check — values fill in automatically.
- Resize the window to see the viewport values, breakpoint indicator and Tailwind/Bootstrap match update live.
- Rotate your device to see orientation and screen sizes update.
- Scroll for GPU vendor/renderer, RAM, network type, audio sample rate, refresh rate and AVIF/WebP/AV1/HEVC codec support.
- Click Copy full report to share or paste in a bug report.
Frequently asked questions
What is device pixel ratio?
How many physical pixels make up one CSS pixel. A Retina display reports 2× or 3× — so a 1440-wide screen actually has 2880 physical pixels horizontally.
Why is my screen smaller than my monitor's spec?
The reported screen size is in CSS pixels and reflects OS scaling settings. Multiply by device pixel ratio to get the physical resolution.
How is refresh rate measured?
By sampling requestAnimationFrame intervals over ~60 frames and taking the median frequency. The result is approximate but typically within ±1 Hz of the panel rate.
How accurate is the GPU detection?
It reads WebGL's UNMASKED_RENDERER_WEBGL and UNMASKED_VENDOR_WEBGL strings. Some browsers obfuscate the value for privacy, so you may see a generic name instead of the real chip.
Why is my codec support different from a friend's?
Codec support varies by browser, version, OS and even hardware. AVIF, AV1 and HEVC in particular have uneven support — that's the point of checking.
Why does my 4K monitor show as 1920×1080?
What you're seeing is the CSS pixel size — what the browser uses for layout. The physical resolution is CSS pixels × device pixel ratio. macOS 'looks like 1920×1080 on Retina' produces 1920 CSS × 2 DPR = 3840 physical pixels. Windows DPI scaling at 200% does the same thing.