Google PageSpeed Insights (https://developers.google.com/speed/pagespeed/insights/) can be used to measure the performance of a page for mobile devices. PageSpeed fetches the URL twice, once for the desktop user agent and once for the mobile user-agent.
The PageSpeed gives a score of 0 to 100 points to your page, and a higher score is better. If you can get more than 85 points on a page, it will indicate that the page is performing well. However, this tool is being continually improved, and the score will differ from time to time.
PageSpeed Insight gives feedback on two areas, how to improve the page performance: