CSS pixels vs Device pixels
When measuring in pixels on the web, you measure in CSS pixels. One CSS pixel often spans multiple physical device pixels on Retina displays.
Developer & Design Use Cases
- Checking UI alignment: Measure margins, padding, and layout spacing of on-screen elements directly.
- Image dimensions: Find out the actual rendered width and height of images on a webpage.
- Responsive design: Measure breakpoints to see exactly when layouts shift on your specific monitor.