What Is My Screen Resolution? Free Screen Resolution Checker & Display Diagnostics
Check your screen resolution, browser viewport, DPR, color depth, and display scaling instantly. The tool runs in your browser, so your display data stays private and updates live as you resize or change screens.
Use our interactive canvas to inspect your active screen metrics, test color rendering, or estimate your monitor's physical dimensions. All calculations run entirely client-side for complete privacy.
🛠️ How this checker works
🖥️ Screen resolution
The browser-reported screen size retrieved from standard client-side Screen APIs.
📊 Viewport size
The active visible content area of the browser window, useful for responsive web design testing.
⚙️ Device Pixel Ratio (DPR)
The scaling factor ratio between logical CSS pixels and physical hardware display pixels.
📐 Estimated physical pixels
Calculated approximately by multiplying the logical CSS viewport dimensions by the detected DPR value.
🔍 Why your screen resolution result may look different
If the detected dimensions do not match the manufacturer specifications of your phone, laptop, monitor, or tablet, it is typically due to display scaling or browser configurations. Here is how to diagnose differences:
| Cause | Why it happens | What to check |
|---|---|---|
| Logical CSS Pixels | Browsers report dimensions in logical CSS pixels to keep website layouts readable. Standard mobile displays render using scaling offsets. | Multiply logical CSS width/height values by your detected Device Pixel Ratio (DPR) to estimate hardware pixels. |
| OS Display Scaling | Windows (e.g. 125% or 150% scaling) and macOS display scaling configurations compress logical viewport areas to prevent tiny text on high-DPI screens. | Check your display scaling configuration inside system preferences (Windows Display Settings or macOS Displays). |
| Active Browser Zoom | Zooming in or out dynamically changes the browser's internal pixel mapping, shifting layout viewport sizes up or down. | Reset browser zoom settings to 100% (use shortcut Ctrl + 0 or Cmd + 0) for a standard baseline check. |
| Mobile Chrome & Bars | Mobile browser address bars, dynamic headers, bottom navigation menus, and keyboard overlays change the active viewport height. | Scroll down the page. Swiping down usually auto-hides address bars and maximizes the available viewport canvas height. |
| Browser Window Borders | Window borders, vertical scrollbars, developer console panels, and desktop toolbars reduce the logical viewport space. | Maximize your browser window or enter Fullscreen mode (use our Fullscreen Test Mode widget below) for direct hardware comparisons. |
| Multi-Screen Setups | Browsers query specifications from the active screen where the browser window is currently positioned. Moving a window across screens shifts the target. | Drag your browser window entirely onto the secondary monitor to view its corresponding display parameters. |
🌐 Browser support and limitations
Different browsers handle screen queries and interface permissions uniquely. Below is the diagnostic feature compatibility matrix across popular browser engines:
| Diagnostic Feature | Chrome & Edge | Safari (iOS/macOS) | Firefox | Limitations / Requirements |
|---|---|---|---|---|
| Screen Resolution | Supported | Supported | Supported | Returns active screen dimensions using client Screen APIs. |
| Viewport Sizing | Supported | Supported | Supported | Calculates visible content area. Updates dynamically on resize. |
| DPR Sizing factor | Supported | Supported | Supported | Reflects OS scaling and browser-level zoom configurations. |
| Fullscreen Testing | Supported | Limited support | Supported | Requires direct user click. iOS Safari has restricted iframe behaviors. |
| Multi-Screen Querying | Permission dependent | Not available in some browsers | Not available in some browsers | Requires the modern Window Management API and user permission prompts. |
* Note: Multi-screen detection may depend on browser support, permissions, and Window Management API availability. External display diagnostic queries dynamically match parameters of the active monitor displaying the browser window.
📐 PPI and screen size calculator
⚙️ CSS media query helper
@media (min-width: [width]px) {
/* Styles for [width]px and wider */
}@media (max-width: [width]px) {
/* Styles for [width]px and narrower */
}@media (-webkit-min-device-pixel-ratio: [dpr]),
(min-resolution: [dpi]dpi) {
/* Styles for [dpr]x pixel density */
}@media (orientation: [orientation]) and (min-width: [width]px) {
/* Matches current orientation + width */
}/* Tailwind breakpoint: [breakpoint] */ /* Your viewport: [width]px × [height]px */ /* DPR: [dpr]x */
🖥️ Browser and device environment
📏 Aspect ratio calculator
📏 Live breakpoint ruler
📱 Responsive preview sandbox
🖥️ Fullscreen test mode
Enter fullscreen to compare your windowed viewport against full display area.
🖥️ Multi-screen detection
Multi-screen detection requires the modern Window Management API.
Supported in Chrome 100+ and Edge 100+. Not available on Safari or Firefox.
Popular developer checks
🔗 Real-time resolution embed widget
Enhance your blog, portfolio, or documentation page by embedding our real-time, responsive screen resolution checker. It runs client-side and is designed to work without external dependencies, fitting seamlessly into any HTML environment.
Understanding Screen Resolution
Have you ever noticed that text looks razor-sharp on one laptop but slightly fuzzy on another? This difference is determined by the display's native pixel density, which is the number of physical pixels packed into the screen area.
Physical resolution is calculated by multiplying the horizontal and vertical pixel counts (such as 1920 x 1080 for a standard Full HD monitor). More pixels mean the display can render finer details, resulting in a cleaner and crisper view.
To check the active specifications of your screen, our online tool detects them instantly using standard browser APIs. It is a convenient way to inspect display metrics on any phone, tablet, or desktop screen without installing extra software.
Choosing a monitor? See our full 1080p vs 1440p vs 4K comparison for resolution-by-size recommendations, PPI guidance, refresh-rate tradeoffs, and common buying mistakes.
Why Resolution Matters
For web designers and developers, knowing screen dimensions helps you decide where to place responsive layout breakpoints. Setting breakpoints for typical laptop and mobile widths ensures that websites look correct across different screens.
Gamers also care about resolution. Rendering high resolutions like 4K requires a powerful graphics card, so some drop their game resolution to 1080p to achieve a smoother, higher frame rate. For general productivity, a higher resolution screen simply provides more room to run windows side-by-side.
Display Grid vs. Viewport Size
These two numbers can be confusing. Your physical display grid represents the actual pixel panel of the screen itself.
Your browser viewport, however, is the actual visible space inside the browser window. Because the viewport excludes the address bar, bookmarks, tabs, and scrollbars, it is almost always smaller than your screen's physical limits.
What is My Screen Aspect Ratio?
An aspect ratio is the proportional relationship between a display's width and height. For example, a 1920x1080 screen has a widescreen ratio of 16:9, while many newer laptops use a taller 16:10 or 3:2 layout to show more vertical content. The checker tool automatically calculates this ratio based on the active viewport metrics.
CSS Pixels vs. Physical Pixels
If you have ever exported a design at 1920px wide and found it looked blurry on a modern laptop, you have experienced Device Pixel Ratio (DPR) at work. High-density screens (like Apple Retina or OLED displays) pack two or three physical pixels into a single CSS pixel unit.
A mobile device reporting a viewport of 390x844 CSS pixels at a DPR of 3 actually has a hardware grid of 1170x2532 physical pixels. To keep images looking sharp on high-density screens, assets should be exported at 2x or 3x scaling.
Reference: W3C CSS Absolute Lengths Specification
Common Display Resolutions
- 1366x768 (HD): Common on older laptops and budget notebooks
- 1920x1080 (Full HD): The universal standard for monitors and web content
- 2560x1440 (QHD): A popular middle ground for creative work and gaming
- 3840x2160 (4K UHD): Offers premium detail for home entertainment and professional design
- 390x844: Standard logical viewport size for modern smartphones
Refresh Rate and Display Connections
Resolution is only part of the story. A screen's refresh rate (measured in Hz) determines how many times per second the display updates its image. Standard office displays run at 60Hz, while gaming monitors often support 144Hz, 240Hz, or higher for smoother motion.
| Resolution & Refresh Rate Choice | Best For |
|---|---|
| 1080p 240Hz/360Hz | Competitive esports |
| 1440p 144Hz/165Hz/240Hz | Balanced PC gaming |
| 4K 60Hz | Productivity and media |
| 4K 120Hz/144Hz | Premium gaming, high-end GPU |
Your video cable must also support your monitor's resolution and refresh rate. For example, older HDMI 1.4 cables can carry a 4K signal, but only at a choppy 30Hz.
For a smooth 4K experience, you will need an HDMI 2.0+ or DisplayPort 1.4 connection. If your screen resolution looks correct but animations feel sluggish, check your connection bandwidth first.
Data source: StatCounter Global Stats
Frequently Asked Questions
What is my screen resolution? ▼
Why is my browser viewport different from my screen resolution? ▼
What does Device Pixel Ratio (DPR) mean? ▼
Why does my phone report fewer pixels than advertised? ▼
What is 4K resolution? ▼
Read our full 1080p vs 1440p vs 4K guide →Source: Wikipedia — 4K Resolution
How do I change my screen resolution? ▼
What CSS breakpoints should I use in 2026? ▼
How do I check screen resolution on Windows? ▼
Read our full Windows resolution guide →Source: Microsoft Support — Change Screen Resolution
How do I check screen resolution on macOS? ▼
Read our full Mac resolution guide →Source: Apple Support — Change Display Resolution
Does this tool collect any data? ▼
What is the difference between screen resolution and screen size? ▼
Read our full Screen Size vs Resolution guide →Source: Wikipedia — Pixel Density (PPI)
What is the most common screen resolution? ▼
🪙 Sourcing, accuracy, and editorial standards
🛡️ Client-side privacy and data handling
The checker runs in your browser using standard Web APIs. Screen and viewport values are calculated locally and are not sent to our first-party servers. Third-party services such as Google AdSense may set cookies based on your consent choices.
✅ Technical sourcing and editorial policy
All pixel counts, viewports, and grids reference official W3C CSS Specifications. We combine this with global tracking from StatCounter, with every diagnostic snippet verified by J. Hassan. Content and diagnostics are reviewed under our editorial policy and testing methodology for technical accuracy, browser API behavior, display terminology clarity, and privacy explanation.
Notice: Browser-reported values may vary due to active browser zoom, OS display scaling, DPR settings, and browser sandbox API limitations.