I was recently working on a new responsive website project, and I realized, there are no good tools to check the responsiveness of a website – so I made a quick and easy tool to do the same. You can find it at http://responsivedesigntest.com/
I have added the most commonly used device sizes, including that of an iPhone and an iPad, so you can test how your website will behave when viewed in an iPhone/iPad, pretty soon I will extending this to include your own custom sizes as well.
Any feedback/suggestions are very much appreciated.
Its very easy to use, here is a screenshot if you are interested.