Faster loading pages will get a boost in result rankings.
Google has started ranking webpages by the speed with which they load.
The search giant is using the loading speeds to help rank the lists of sites it produces in response to keyword queries.
Google said it had taken the action because studies have shown that web users much prefer to visit sites that load quickly.
However, it said the change would only affect the rankings of a very small number of webpages.
Before now Google's ranking of results has been based on the relevance of the text on a webpage and how many other sites refer to it as a good source of information.
To this Google has decided to add an extra metric in the form of the speed with which pages show up when users click on a link or type in an address.
In a blog posting explaining the policy change, engineers Amit Singhal and Matt Cutts said internal studies at Google had revealed that when sites take too long to load people do not visit as much.
Other studies have shown that these delays can have long-term effects as people remember their experience and become reluctant to return to slower sites.
Google also provided links to tools that website owners can use to see how fast their pages load and find help to make them show up even more quickly.
Despite the change, Google said the most important criteria for ranking results would remain the relevance of a page to a particular query. It said that only about 1% of search queries will be affected by the change to include load speed.