If you are a site owner, webmaster or a web author, here are some free tools that you can use to evaluate the speed of your site:Page Speed, an open source Firefox/Firebug add-on that evaluates the performance of web pages and gives suggestions for improvement.YSlow, a free tool from Yahoo! that suggests ways to improve website speed.WebPagetest shows a waterfall view of your pages' load performance plus an optimization checklist.In Webmaster Tools, Labs > Site Performance shows the speed of your website as experienced by users around the world as in the chart below. We've also blogged about site performance.Many other tools on code.google.com/speed.While site speed is a new signal, it doesn't carry as much weight as the relevance of a page. Currently, fewer than 1% of search queries are affected by the site speed signal in our implementation and the signal for site speed only applies for visitors searching in English on Google.com at this point. We launched this change a few weeks back after rigorous testing. If you haven't seen much change to your site rankings, then this site speed change possibly did not impact your site.