A new web usability tool from Google, Google Browser Size is a visualization of browser window sizes for people who visit Google. For example, the “90%” contour means that 90% of people visiting Google have their browser window open to at least this size or larger.

This is useful for ensuring that important parts of a page’s user interface are visible by a wide audience. On the example page that you see when you first visit this site, there is a “donate now” button which falls within the 80% contour, meaning that 20% of users cannot see this button when they first visit the page. 20% is a significant number; knowing this fact would encourage the designer to move the button much higher in the page so it can be seen without scrolling.

Using this tool is easy, you just simply enter URL in the text box, then the web will load in the background and let you see how many percent of visitors can view any parts of web page.

Link : Google Browser Size