What does Screen Resolution Checker do?
Inspect screen and layout dimensions instantly.
Detecting your screen…
Inspect screen and layout dimensions instantly.
Detecting your screen…
Inspect screen and layout dimensions instantly. Use it in your browser without uploading files for typical workflows.
A screen resolution checker shows your device’s screen resolution, viewport size, and related metrics like device pixel ratio (DPR) and CSS pixels. It’s used to debug responsive layouts, confirm breakpoints, diagnose scaling and zoom issues, and document environment details for QA and support.
Use it to understand the difference between physical pixels and CSS pixels (viewport) so responsive designs behave predictably.
Concise answers for common searches — definitions, steps, and comparisons.
Inspect screen and layout dimensions instantly.
Screen Resolution Checker (/screen-resolution-checker) runs in your browser when supported—inputs are not uploaded to EverydayTools servers.
Screen resolution describes physical device pixels. Viewport describes the browser’s layout area in CSS pixels. Device pixel ratio (DPR) relates the two: device pixels ≈ CSS pixels × DPR. Responsive CSS breakpoints use viewport width in CSS pixels.
Formula
Approx relationship: device pixels = CSS pixels × DPR (ignoring zoom and OS scaling).Run the checker on the exact device/browser you’re debugging so the reported viewport and DPR match the real environment.
Screen resolution is the device’s pixel grid; viewport is the browser’s usable area in CSS pixels. Responsive breakpoints follow viewport width.
DPR affects how many device pixels represent one CSS pixel. Browser zoom and OS scaling can change effective metrics, so note DPR and zoom state.
Compare viewport width to your breakpoint thresholds (sm/md/lg) to confirm which responsive rules should apply.
Input
Device: 2560×1440 screen; DPR: 2; browser viewport: ~1280×720 CSS pxOutput
Breakpoints use 1280 CSS px, not 2560 physical pxHigh-DPI screens often report fewer CSS pixels than physical pixels because DPR > 1.
Input
Mobile address bar expands/collapsesOutput
Viewport height changes while screen resolution remains constantOn mobile, browser UI affects viewport size; responsive issues often come from height changes during scroll.
Common real-world scenarios where this tool saves time.
Frontend developers
Confirm which breakpoints should apply based on viewport width and DPR, not just device marketing resolution.
QA teams
Capture screen, viewport, and DPR in bug reports so developers can reproduce issues accurately.
Designers
Understand how CSS pixels map to physical pixels so typography and spacing look consistent across devices.
Support and ops
Identify whether a user’s issue comes from browser zoom, OS scaling, or device pixel ratio differences.
How this EverydayTools page compares for typical use.
| Aspect | EverydayTools | Typical alternative |
|---|---|---|
| Cost | Free | Paid apps or trials |
| Privacy | Browser-local when supported | Often requires cloud upload |
| Signup | Not required | Often required |
Breakpoints are based on viewport width in CSS pixels, not physical pixels. Use viewport width for responsive decisions.
High-DPI screens can render differently. Check DPR and confirm images and canvas elements are scaled appropriately.
Zoom changes effective CSS pixels and can alter layout. Verify zoom is at 100% when debugging breakpoints.
Likely cause: Browser UI chrome and orientation changes can affect viewport size.
Fix: Test with the address bar expanded/collapsed and in both orientations; rely on CSS techniques that adapt to viewport changes.
Likely cause: Viewport is measured in CSS pixels and affected by DPR and scaling.
Fix: Use viewport width and DPR to explain breakpoint behavior; marketing resolution is physical pixels.
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Screen size is the device’s pixel dimensions. Viewport size is the browser’s usable layout area in CSS pixels. Responsive breakpoints use viewport width, not physical screen pixels.
DPR is the ratio between physical device pixels and CSS pixels. A DPR of 2 means one CSS pixel maps to about 2×2 device pixels. High-DPI screens often have DPR > 1, which changes how big things look in CSS pixels.
Mobile browsers show/hide UI elements like the address bar, which changes the available viewport height. This can cause layout jumps if the design depends on viewport height measurements.
Breakpoints depend on viewport width in CSS pixels. DPR affects how CSS pixels map to physical pixels, but the breakpoint logic itself uses the viewport width.
Inspect screen and layout dimensions instantly.
Screen metrics are read locally in your browser and are not uploaded to a server.
Values come from browser APIs and reflect current zoom, scaling, and device characteristics.
Different browsers can report metrics differently. Use results as a debugging reference, not as a hardware specification sheet.
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Reviewed by EverydayTools Editorial Team on 2026-04-30.