InTwo alternatives

A tool for designers to measure screen dimensions This extension measures the dimensions from your mouse pointer up/down and left/right until it hits a border. So if you want to measure distances between elements on a website this is perfect. It doesn't really work with images because there the colors change a lot pixel to pixel.

MeasureMate the ultimate tool for measuring distances between elements on webpages. It lets you just select the element and then check all the distances to any other element. You can select the whole element or only the content box.