Screen Resolution Checker

Check your screen, viewport & pixel-ratio instantly.

Instantly see what is my screen resolution — your display's physical pixel size, your browser's live viewport in CSS pixels, device pixel ratio for Retina/HiDPI screens, color depth, orientation and aspect ratio. Also runs a live refresh-rate (Hz) meter and an HDR/color-gamut check. Updates live as you resize the window or rotate your device, with a built-in breakpoint tester for responsive design. 100% client-side.

About Screen Resolution Checker

Screen Resolution Checker features

How to use Screen Resolution Checker

  1. Open the page

    Your screen and viewport size are read the moment the page loads — no button to press.

  2. Read the headline result

    The dark card at the top shows your screen resolution, aspect ratio and live viewport size in one glance.

  3. Measure your refresh rate (optional)

    Click Measure refresh rate to get a live Hz estimate of your actual monitor — handy for confirming a 120Hz/144Hz display is really running at full speed.

  4. Resize or rotate to test

    Drag your browser window's edge, zoom, or rotate a phone/tablet — every number updates live.

  5. Check a breakpoint (optional)

    Pick a common device width from the dropdown to see whether your current viewport meets it — handy for quick responsive-design checks.

Best practices

CSS pixels vs physical pixels

Your screen's physical resolution and the browser's CSS-pixel viewport are different measurements. A device pixel ratio (DPR) of 2× means one CSS pixel is drawn using a 2×2 grid of physical pixels — which is why 'Physical resolution' above is larger than the plain screen figure once DPR is factored in.

Why 1366×768 isn't exactly 16:9

Some very common laptop resolutions are marketing shorthand rather than exact ratios — 1366×768 is actually 1.7786:1, just barely off true 16:9 (1.7778:1). This tool snaps close matches to their well-known ratio label so it stays readable, and falls back to the exact simplified fraction otherwise.

What HDR and wide color gamut mean

Standard displays cover the sRGB color space. Wide-gamut displays (Display P3, common on modern phones and Macs) can show noticeably more vivid reds and greens. HDR (high dynamic range) goes further, allowing much brighter highlights and deeper blacks in supported content — but only when your OS, display, browser and the content itself all support it.

A 'Not detected' HDR result can simply mean your OS isn't currently in HDR display mode, even on HDR-capable hardware.

Popular use cases

Responsive design

Test CSS breakpoints against your real, live viewport size.

Buying a monitor

Confirm your display's actual native resolution before changing settings.

Gaming refresh rate

Verify a 120Hz/144Hz monitor is really rendering at full speed.

HDR content

Check whether your screen + browser combo actually supports HDR/wide gamut.

Retina assets

Confirm your device pixel ratio before exporting 2× / 3× image assets.

Bug reports

Copy or export the exact screen/viewport specs for a support ticket.

Frequently asked questions

What is my screen resolution?

The dark headline card above shows your display's native pixel dimensions, read live from window.screen — e.g. 1920 × 1080 for a Full HD monitor.

Why are 'screen resolution' and 'viewport' different numbers?

Screen resolution is your monitor's total physical pixels. The browser viewport is only the usable area inside the browser window (minus toolbars, and after browser zoom is applied) measured in CSS pixels — it's almost always smaller than the full screen, and it's the number that actually controls your CSS media queries.

How accurate is the refresh-rate meter?

It counts real animation frames delivered by your browser over one second, which normally lines up closely with your monitor's true refresh rate. It's an estimate, not a certified measurement — background tabs, battery-saver mode or a heavily loaded system can temporarily throttle it lower than your display's real rate.

What is device pixel ratio (DPR)?

It's the ratio between physical screen pixels and CSS pixels. A DPR of 2× (common on Retina/HiDPI screens and most phones) means every CSS pixel is drawn with 2×2 physical pixels — so images and icons need to be exported at 2× or 3× resolution to look sharp.

Why does my resolution change when I zoom the browser?

Browser zoom changes how many CSS pixels fit in your window, which changes the reported viewport size — but your screen's physical resolution stays the same. That's expected: zoom only affects the viewport reading, not the screen reading.

Does this tool track or store my screen size?

No. Everything is read directly from your browser's window.screen API and displayed locally. Nothing is sent to a server, logged or stored.

Why would I need to check my screen resolution?

Common reasons: debugging a responsive-CSS layout that breaks at a certain width, confirming your monitor's native resolution before changing display settings, exporting correctly-sized images for Retina screens, checking a high-refresh-rate monitor, or filling in a bug report.

Related tools — Site diagnostics