Screen Resolution Checker

Instantly see your screen resolution, viewport size, device pixel ratio, and orientation.

Screen and viewport sizeDevice pixel ratioBrowser-based checkNo account needed

Screen resolution checker

Values are detected locally in your browser. Resize your browser to update viewport values.

Screen resolution

800 × 600

Full display size reported by the browser.

Viewport size

800 × 600

Visible browser content area used by webpages.

Available screen

800 × 600

May exclude taskbars, docks, or system UI.

Device pixel ratio

1

Maps CSS pixels to physical display pixels.

Orientation

portrait-primary

Detected through browser APIs or viewport shape.

Breakpoint category

Tablet

Based on current viewport width.

Color depth

24-bit

Color information exposed by the browser.

Pixel depth

24-bit

Pixel depth reported by the display API.

Screen size and browser viewport size are not always the same. Device pixel ratio affects how CSS pixels map to physical pixels.Last updated: 14:16:23

Local browser check

Screen and viewport values are detected locally with browser APIs.

Resize-aware

Viewport values update when the browser is resized or orientation changes.

Copy-ready results

Copy a clean summary for debugging, QA notes, or design handoff.

Dynamic Screen Insights

Your viewport is currently 800 × 600 CSS pixels.
Your device pixel ratio is 1, so one CSS pixel may map to multiple physical pixels.
Your screen is in portrait orientation.
The browser viewport can change when you resize the window or open developer tools.
Responsive breakpoints should usually use viewport width, not full screen width.

How Screen Resolution Checking Works

Browser APIs

Browsers expose screen and viewport dimensions through JavaScript APIs.

Screen size

Screen resolution describes the display area reported by the browser.

Viewport size

Viewport size describes the visible browser content area.

Available size

Available screen size may exclude operating system UI areas.

DPR

Device pixel ratio explains scaling between CSS pixels and physical pixels.

Screen Size, Viewport, DPR, and CSS Pixels Explained

Screen size

The full display size reported by the browser.

Viewport size

The current browser content area used by webpages and media queries.

Available screen

May exclude taskbars, docks, browser UI, or operating system areas.

CSS pixels

Layout units used by webpages.

Physical pixels

Hardware display pixels on the device panel.

Device pixel ratio

The link between CSS pixels and physical pixels on high-DPI screens.

Responsive Design and Browser Testing Notes

Use viewport width

Responsive layouts should usually rely on viewport width.

Device vs viewport

Device width and viewport width can differ.

Browser zoom

Zoom may affect reported CSS pixel dimensions.

Mobile UI

Mobile browser address bars can change viewport height while scrolling.

Dev tools

Developer tools can simulate viewport sizes for testing.

Real devices

Important layouts should still be checked on real devices when possible.

Common Screen Resolution Examples

360 × 800

Mobile viewport

390 × 844

Modern phone viewport

768 × 1024

Tablet viewport

1366 × 768

Laptop display

1440 × 900

Laptop display

1920 × 1080

Full HD desktop

2560 × 1440

QHD display

3840 × 2160

4K display

Developer, Design, and QA Use Cases

Responsive design testing
Frontend debugging
Mobile viewport checks
Browser resize behavior
QA screenshots
Design handoff checks
Breakpoint planning
Compatibility testing
High-DPI display checks
Layout bug reports

Privacy and Local Processing Notes

Local detection

Screen details are read locally in your browser.

No account

No sign-up or account is required.

No backend storage

Results are not sent to a server by this tool.

Copy control

Copied values stay under your control.

Lightweight testing

The tool is intended for responsive testing and display debugging.

Simple browser APIs

The checker uses standard browser properties where supported.

Method Explanation

1. Load the page in a browser.
2. Read screen dimensions from the browser’s screen object.
3. Read viewport dimensions from the current window size.
4. Read device pixel ratio and orientation where supported.
5. Update viewport values when the browser is resized.
6. Display copy-ready screen and viewport results.

Frequently Asked Questions

A screen resolution checker detects your display size, browser viewport, device pixel ratio, orientation, and related display details locally in your browser.