Google is about to change the way its influential search engine recommends websites on smartphones and tablets in a shift that's expected to sway where millions of people shop, eat and find information.

The revised formula, scheduled to be released Tuesday, will favor websites that Google defines as "mobile-friendly." Websites that don't fit the description will be demoted in Google's search results on smartphones and tablets while those meeting the criteria will be more likely to appear at the top of the rankings—a prized position that can translate into more visitors and money.