Mobile-friendliness describes how easy a website is to read and use on a smartphone. In SEO it should be kept apart from mobile-first indexing, which decides which version of a page Google uses for indexing.
What has changed at Google?
Google rolled out its mobile-friendly ranking update on April 21, 2015. On December 1, 2023 Google removed mentions of the Mobile-Friendly Test and the Mobile Usability report from its documentation. According to the update entry, both tools are going away. Lighthouse can check issues such as a missing viewport tag. Whether mobile-friendliness is used directly in ranking, Google answers only in general terms. According to its page experience documentation there is no single ranking signal, and mobile-friendliness is named as one of several aspects of a good page experience.
- Google adds a “mobile-friendly” label to mobile search results. It appears for pages that are readable without zooming and avoid Flash.Source: developers.google.com
- Google announces that it will expand its use of mobile-friendliness as a ranking signal for mobile searches from April 21, 2015.Source: developers.google.com
- The mobile-friendly update starts rolling out globally, unofficially called “Mobilegeddon”. It only affects rankings on mobile devices.Source: developers.google.com
- Google removes the “mobile-friendly” label because 85% of pages in mobile results now carry it. Mobile-friendliness remains a ranking signal.Source: developers.google.com
- Google announces mobile-first indexing and starts experimenting. In future, mainly the mobile version of a page is to be used for indexing and ranking.Source: developers.google.com
- After a year and a half of testing, the migration begins. Google first moves sites that follow the best practices.Source: developers.google.com
- Mobile-first indexing becomes the default for all new websites previously unknown to Google Search.Source: developers.google.com
- Google announces that all websites will switch from September 2020. At this point 70% of sites shown in search results have already moved.Source: developers.google.com
- Google postpones the complete switch to the end of March 2021.Source: developers.google.com
- Google declares the move to mobile-first indexing complete. A small set of sites that do not work on mobile is still crawled with desktop Googlebot for now.Source: developers.google.com
- The Mobile-Friendly Test and the Mobile Usability report in Search Console are retired.Source: developers.google.com
- As the final step, Google crawls the remaining sites with the mobile Googlebot after this date. Content that is not accessible on mobile devices at all can no longer be indexed.Source: developers.google.com
Google itself does not use the name “Mobilegeddon”; it comes from the SEO industry. The planned dates of September 2020 and March 2021 were not met; according to Google the switch was only completed in October 2023. Last checked: .
What matters in practice?
Google recommends responsive web design as the easiest setup: the same URL and the same HTML for every device. Dynamic serving and separate mobile URLs are alternatives. Google states that it uses the mobile version of a page for indexing and ranking, and that only content shown on the mobile version is used for indexing. A page therefore needs the same content, structured data and meta information on mobile as on desktop.
A viewport meta tag is part of the setup. Without it, Lighthouse notes, mobile devices render the page at desktop width and scale it down, which makes it hard to read.
Example
A shop shows a specifications table on desktop but hides it on phones. Visitors can still use the page, but the table is missing from what Google indexes.
Sources
- Mobile sites and mobile-first indexing – Google Search Centraldevelopers.google.com
- Latest documentation updates (entry of Dec 1, 2023) – Google Search Centraldevelopers.google.com
- Document has a viewport meta tag – Lighthousedeveloper.chrome.com
- Rolling out the mobile-friendly update – Google Search Central Blog (Apr 21, 2015)developers.google.com
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