r12

What is r12?

r12 is a lightweight grid overlay for inspecting layout structure on the web. Visualize 12-column, modular, baseline, and rule-of-thirds systems directly on any site to check alignment and spacing in real context. Designed for speed and simplicity; no setup, no friction, just a quick way to bring structure into your workflow. Inspired by Swiss design principles. Already used by designers and developers, and featured on the Chrome Web Store.