What Is a Screen Resolution Tool?
A screen resolution tool detects and displays your current screen dimensions, pixel density, device pixel ratio, and viewport size. This information is essential for web developers testing responsive designs, designers creating assets at the correct resolution, and users troubleshooting display issues or choosing monitor settings.
How to Use This Screen Resolution Tool
- Open this page on the device whose screen you want to measure.
- View your screen resolution (width × height in pixels), device pixel ratio (DPR), viewport dimensions, and color depth.
- Resize your browser window to see the viewport dimensions update in real time, useful for testing responsive breakpoints.
Key Concepts
Screen resolution is the total number of pixels a display can show, expressed as width × height (e.g., 1920×1080). The device pixel ratio (DPR) indicates how many physical pixels correspond to one CSS pixel—Retina displays typically have a DPR of 2 or 3. The viewport is the visible area of the browser window, which may be smaller than the screen resolution due to toolbars, taskbars, and browser chrome.
Frequently Asked Questions
What is the difference between screen resolution and viewport size?
Screen resolution is the total pixel count of your physical display. Viewport size is the area available for rendering web content within the browser, excluding toolbars, scrollbars, and the browser frame. Responsive CSS media queries target the viewport, not the screen resolution.
What is device pixel ratio?
Device pixel ratio (DPR) is the ratio of physical pixels to CSS pixels. A DPR of 2 means each CSS pixel is rendered using a 2×2 grid of physical pixels, producing sharper text and images on high-DPI screens like Apple Retina displays.
Why does my reported resolution differ from my monitor specs?
Operating system display scaling may reduce the effective resolution. For example, a 4K monitor (3840×2160) at 200% scaling reports as 1920×1080 CSS pixels to the browser, even though the physical panel has four times as many pixels.