The MeasureMate is a simple and helpful tool to measure distances on a webpage with one click. You can measure the distance between the selected element and any other element. You can measure the distance between the content box and the entire page, the distance between two images, or the distance between two links.

It is browser extension that you can simply download and start using. Once installed, you can place the cursor over the element and start measuring. 

This extension will not cause any interference unless you choose to activate it.