Calipers vs Page Ruler Redux
Page Ruler Redux is a lightweight pixel ruler for Chrome. Calipers extends that idea with multi-element measurement, guides, box model inspection, and more.
The short version
If you only need a simple ruler overlay, Page Ruler Redux works well. If you regularly check spacing between UI elements, verify alignment against a design spec, or inspect box model values during QA, Calipers is built for that workflow.
Comparison
| Feature | Calipers | Alternative |
|---|---|---|
| Hover dimensions | Yes — Inspect mode | Yes |
| Measure distance between elements | Yes — up to 5 elements at once | Basic ruler only |
| Alignment guides | Yes — draggable, persisted | No |
| Box model overlay | Yes | No |
| Snap to element edges | Yes | No |
| Design token extraction | Yes | No |
| Screenshot export | Yes — with measurements | No |
| Keyboard shortcuts | Full keyboard-first workflow | Limited |
| Open source | Yes (MIT) | No |
What Calipers adds
Click two elements in Measure mode and Calipers shows the pixel gap between their closest edges — with alignment guidelines drawn automatically. Switch to Guides mode to pin horizontal and vertical lines that snap to element edges. Toggle the box model overlay to see margin, padding, and border values without opening DevTools.
Related
See also Calipers vs PixelSnap or the frontend QA guide.