When we were planning the redesign of shockwave.com we had a number of design elements that had specific width requirements. Ads, game content, and a variety of items needed to fit onto one design grid. We needed a quick way to iterate through a number of different column and margin widths and doing it by hand was too inefficient.
So I built this grid tool to help us narrow down our options. After refining it with a few more features I realized it might be useful for the web design community and released it into the wild. I’ve had great feedback and plan to add new functionality soon.