Calipers

Precision measurement for the web — inspect dimensions, measure distances, and check alignment on any webpage.

Calipers is a free, open-source browser extension for designers and engineers who care about precision. Hover over any element to inspect its dimensions, box model, CSS path, and typography. Click two elements to measure the distance between them. Drop alignment guides on the page that snap to element edges. Pick colors and copy them as HEX, RGB, or HSL. Reveal spacing gaps between sibling elements instantly with the Spacing Grid. Everything PixelSnap does — built for the browser. MODES 1. Inspect — Dimensions, box model, CSS path, typography & viewport distances 2. Measure — Click up to 5 elements, all gaps measured simultaneously 3. Guides — Draggable guides with snap-to-element edges, persisted across sessions 4. Colour Picker — Sample element colours and copy as HEX, RGB, or HSL 5. Spacing Grid — Show all gaps between sibling elements at once Open source. No tracking. No account required.