Help & FAQ

    Common questions about using ScreenRes.tools.

    What is ScreenRes.tools?

    ScreenRes.tools is a free, browser-based suite of screen and display diagnostic tools. It detects your screen resolution, pixel density, refresh rate, and more, all without downloads or installations.

    How does resolution detection work?

    We use the browser's window.screen and devicePixelRatio APIs to read browser-reported screen size, viewport size, color depth, and orientation in real time. When those APIs are available, we also show an estimated physical-pixel resolution derived from CSS pixels x DPR.

    Is it accurate on Retina / HiDPI displays?

    Usually, yes, but it is still an estimate. We report both the CSS screen size and an estimated physical (hardware) resolution by multiplying by the device pixel ratio. A 1440x900 MacBook with 2x DPR shows as roughly 2880x1800 physical pixels, but browser zoom and platform quirks can affect that estimate.

    Does the Dead Pixel Test actually detect dead pixels?

    The test fills your screen with solid colors. You visually inspect for pixels that do not match. A dead pixel stays black, a stuck pixel stays a fixed color. Use fullscreen mode and check each color carefully.

    Before you start, we show a photosensitivity warning (the Dead Pixel and Color tests use bright, full-screen colors). If you are sensitive to flashing lights or have photosensitive epilepsy, do not use those tools.

    How accurate is the Refresh Rate test?

    It uses requestAnimationFrametiming to estimate your display's refresh rate. Results are typically within +/-1 Hz of your actual rate.

    Does this work on mobile devices?

    Yes. All tools work on phones and tablets. Some fullscreen tests (Dead Pixel, Backlight) work best on desktop monitors where you can go true fullscreen.

    Is any data collected?

    No. All detection and testing runs entirely in your browser. No screen data, results, or personal information is ever sent to a server. See our Privacy Policy for details.

    Need more help?

    If you have questions or find a bug, open an issue on our GitHub repository or reach out via the contact information in the footer.