The impatience of Internet users with regards to the time it takes to load a Website is a well known fact. A Website's performance and its ability to load quickly are subsequently critical factors in its usability and - more importantly - success. Any one - or perhaps even several - of the following selection of free tools can be incorporated into the process of Web development in order to create faster sites and identify potential performance bottlenecks.

Page Speed Online - This handy Google tool analyses Website performances in accordance with Google's Best Practises for Web Performance, a set of optimal performance (front-end) rules. It provides plenty of information, including reports on best optimal performance practises for mobile devices.

Pingdom Tools - This online Website, network and server monitoring service provides several reports, including, for instance, a breakdown of varying objects' ( images, JavaScript libraries, style sheets, and so on) loading times; browser caching performance grades and page analysis providing information on page sizes, requests and load times.

Other great speed testing tools include:

BrowserMob Website Performance Test
OctaGate SiteTimer
Show Slow
Site-Perf
Web Page Analyzer
WebPagetest
Which loads faster?

The following are also well worth checking out:

GTmetrix
Site Speed Checker
Web Site Performance Test
Website Speed Test (1)
Website Speed Test (2)
Website Speed Test (3)
Webslug
WebWait
Zoompf Web Performance Scan