This ‘How fast is my website?’ web tool is supposed to be pretty good. When testing your website speed be sure to choose the server nearest your location.
Also available is this:
Essential site availability monitoring.
Monitor the availability and accessibility of your website for FREE & get alerted when an incident happens.
Test every minute from +70 locations globally.
This how-fast-is-my-website online test tool includes in the results page many details and ratings of the various items and functions that contribute to the speed of your website’s page loading time.