Responsive websites are the new thing. They automatically move stuff around and change the page design when the screen becomes a certain size, without the need to reload the page or redirect the user.This tool will give you a preview of what your website looks like on certain device sizes.
Starting in 2013 Google has taken a strong stance on mobile SEO, announcing there will be demotions if your site is not mobile friendly or is misconfigured when it comes to being mobile friendly. So the most important is to check if your site has responsive design and also ensure that it loads fast.
Choose a phone or device to preview from. Then provide your URL, and click the button.