Developer and photographer Christopher Kalafarski has created a free tool that enables users to compare and preview various aspect ratios with their own images. Unlike comparisons in an application like Lightroom, Kalafarski points out that his tool is simple to use and offers a wide range of sample ratios.

Users can add their own image to the tool by dragging and dropping them onto the Web page. features an input format box at the bottom, which can be clicked to cycle through multiple format options. Users can enable and disable horizontal and vertical lines, and click lines to crop the image at them.

Though the tool works on mobile devices, Kalafarski explained in a Reddit post that he designed for desktop browsers. The tool operates locally in the browser, meaning user images are not uploaded to a server.