Screen Resolution Test — Check Your Exact Display Resolution Online
Use our free screen resolution test to check CSS pixels, physical pixels, viewport size, and color depth instantly — works on any device or browser.
“What resolution is my screen?” seems like a simple question — but the answer depends on whether you mean CSS pixels, physical pixels, or your OS display resolution. Our free screen resolution test shows all of them at once, directly in your browser with no download or signup required.
This is especially useful when debugging responsive web layouts, setting up a new monitor, configuring display scaling on Windows or macOS, or verifying your device pixel ratio before optimizing images for HiDPI screens.
🖥️ Free Screen Resolution Test
Check CSS pixels, physical pixels, viewport size, pixel ratio, and color depth — instantly in your browser.
What the Tool Shows You
The tool reads these values directly from your browser and OS:
| Value | What It Means |
|---|---|
| CSS Pixels (Width x Height) | The logical resolution your browser uses for layout — affected by OS display scaling |
| Physical Pixels | The actual hardware pixels on your display panel — CSS pixels multiplied by device pixel ratio |
| Viewport Size | The visible area of the browser window — excludes scrollbars and browser chrome |
| Device Pixel Ratio (DPR) | The multiplier between CSS and physical pixels — 2.0 means Retina / HiDPI |
| Color Depth | Bits per pixel your display supports — typically 24-bit (16.7 million colors) |
CSS Pixels vs Physical Pixels — Why You See Two Numbers
This is the most common source of confusion when checking your display resolution. Here is the clear explanation, as defined in the W3C CSS Values specification:
- Physical pixels are the actual hardware dots on your display panel. A 4K monitor has 3840×2160 physical pixels.
- CSS pixels are the logical pixels browsers use for layout. They are scaled by your OS display scaling setting and device pixel ratio (DPR).
- Device Pixel Ratio (DPR) is the multiplier between CSS and physical pixels. A DPR of 2 means 4 physical pixels (2×2) per CSS pixel — this is “Retina” or HiDPI. The tool reports your exact DPR.
Common Resolution Reference Chart
| Resolution Name | CSS Pixels | Physical Pixels | Common Use |
|---|---|---|---|
| HD Ready | 1280×720 | 1280×720 (at 1x DPR) | Old monitors, budget laptops |
| Full HD (1080p) | 1920×1080 | 1920×1080 (at 1x DPR) | Standard desktop monitors |
| 2K / QHD | 2560×1440 | 2560×1440 | Gaming monitors, mid-range laptops |
| 4K / UHD | 1920×1080 CSS (at 200% scaling) | 3840×2160 | Premium monitors, video editing |
| MacBook Pro 14” | 1512×982 CSS | 3024×1964 physical | DPR 2.0 — Retina display |
| iPhone 15 Pro | 393×852 CSS | 1179×2556 physical | DPR 3.0 — Super Retina XDR |
How to Use It — Step by Step
Frequently Asked Questions
Common questions about the screen resolution test and how to read the results.
