Google PageSpeed Insights: A Google page speed test with actionable tips on how to speed up
Google PageSpeed Insights tells you how fast is your website and gives very clear and detailed instructions on how you can improve your performance. Since loading speed is an important ranking factor for Google, this tool is a must.
Google PageSpeed will show you 2 tabs: for mobile and for desktop with green, red or orange score and elements. This color code indicates how well your website is doing. Green (score above 85) means you are ok, orange and red – you need to speed your website up.