The Mobile-First Index: How Google’s Latest Change Will Affect Your Website

by | Last updated Mar 19, 2024 | SEO

Read Time: 5 min read

Summary: TL;DR: Google will switch to a mobile-first index, ditching the desktop index. This change emphasizes mobile-friendly sites for better rankings. Responsive designs are favored, while dedicated mobile sites need revamping. Content hidden behind tabs will now be weighted equally. If you lack a mobile site, your desktop site will still be indexed, but user experience may suffer. Don't rush into mobile presence; ensure thorough testing. The mobile-first index isn't fully live yet, giving time to adapt. Check out recommended articles for more info. Contact Hurrdat for web design and SEO services to make your site mobile-ready. Stay ahead of the game to maintain or improve search rankings.

Back in November, we shared news about Google splitting its desktop and mobile indexes. Over the last month, however, new information has come out that Google will, in fact, be making a huge change to its index, but not in the way we previously thought. There will not be two separate indexes—one for mobile and one for desktop—as was initially reported. There will only be the mobile-first index.

Replacing the desktop index with a new mobile-first index is a monumental change to Google’s 15+ year focus on desktop results in search engine results pages (SERPs). However big a change this is, it shouldn’t come as a surprise. After all, Google has been pushing us to make our websites mobile-friendly for the better part of two years now.

The difference is that, soon, all of the desktop signals we’ve been relying on to rank our websites will now count for nothing. In other words, with the focus moving to mobile, those signals will now be taken from the mobile site rather than desktop. That said, Google’s Gary Illyes and Paul Haahr have mentioned in separate situations that they want there to be minimal disruption to rankings from this change, although it’s too early to say exactly what impact this change will have.

If you’ve been taking heed of Google’s gentle nudges toward mobile optimization, then this change shouldn’t have a major effect on your site’s rankings. However, many sites still aren’t mobile-friendly and could be at risk of losing out on rankings when Google flips the switch.

So what should you do?

Responsive Design

Google has intimated several times over the last couple of years that a responsive design is the preferred method for a mobile site. Having a responsive design means you only have to optimize one set of content, and it uses CSS to display the content differently on a variety of screen sizes.

If you’re currently using a responsive design for your website, you should be in a good position already. However, make sure that the CSS is displaying everything that’s being shown on the desktop site. This is crucial because only content visible on the mobile site will be taken into account by the new mobile-first algorithm. Now is the time to check both versions of your site and ensure they both display exactly the same information. If not, make it so.

Dedicated Mobile Sites

If you have a dedicated mobile site—, for example—then the chances are you’ve got a lot of work ahead of you. Traditionally, implementing the correct canonical tags pointing between the desktop and mobile versions of the site was all you needed to rank your mobile site (which, thankfully, you will not have to change), provided that the desktop site was already well-optimized.

Google’s algorithm used the signals from the desktop site, applied them to the mobile site, and indexed the URLs accordingly. This meant that it wasn’t necessarily as important to optimize your mobile site to the same extent or even display the same level of information as the desktop. This is all about to change.

Even if you had been paying attention to Google’s advice and made sure your site had the mobile-friendly tag in the SERPs, you may still have some work to do. The mobile-friendly tag is merely an indication that the site displayed correctly on mobile devices. That alone won’t be enough to satisfy the new index, your mobile site will need to be as optimized as the desktop version.

You’ll need to audit what both sites are displaying in order to evaluate what needs to be done in preparation for the update. Any pages that appear on the desktop site but not on the mobile site will result in the desktop site ranking in the SERPs. This is not optimal but better than nothing.

The problem occurs when there is a cut-down version of the content of the mobile site. The Googlebot will see that page exists on the mobile site and thus completely ignore the desktop page, evaluating only the mobile version content. If that page only contains a fraction of the content that exists on the desktop site, your rankings for that page could be in serious jeopardy.

How do you fit all of the content from a desktop page into a tiny mobile device display? Google doesn’t like us using tabs or accordions to organize our content, so you’ll have to have pages that scroll forever, right?


Good news, everyone! Google’s Gary Illyes confirmed on Twitter that content hidden behind a tab or accordion WILL be weighted the same as content not hidden behind a tab or accordion. This is the complete opposite of how the Googlebot currently handles content hidden behind tabs on desktop sites.

What If You Don’t Have a Mobile Site?

Even if, despite all of the hints from Google, you still don’t have a mobile presence, all is not lost. You can still rank in the mobile-first index without actually having a mobile website. Yes, you read that right! Google said, “If you only have a desktop site, we’ll continue to index your desktop site just fine, even if we’re using a mobile user agent to view your site.”

If the Googlebot doesn’t detect a mobile page for that URL, it will crawl the desktop version. However, take the time to use a mobile “fetch and render” tool to see if your desktop site actually renders fully on mobile devices. That’s where this could lead to a problem. Your desktop site will still rank in a mobile-first index, but when someone lands on your site on a mobile device, the user experience will likely lead them right back to the SERPs.

This is the optimum time to be thinking about creating a mobile presence online, whether that’s using a new responsive design or creating a dedicated mobile website. However, be warned. Do not rush into creating a mobile presence that isn’t complete—this could hurt more that help you. Do not launch anything new unless it has been thoroughly tested, and the finished product reflects the information equally on both desktop and mobile.

Final Thoughts

The good news is that Google’s new mobile-first index isn’t live yet. Yes, they’re testing it in a few very small markets to a limited number of users, but it isn’t live en masse. There’s still time to ensure your site isn’t affected negatively by the change.

If you want more information on this change, here are a few excellent articles we recommend you read:

Or contact Hurrdat today to learn more about our Custom Web Design and SEO services to help get your website mobile first ready!

Ross Allen


Ross Allen is a man of diverse interests, including craft beer, golf, and spending quality time with his wife. However, his true passion lies in search engine optimization (SEO), a field he excels in as the SEO Director at Hurrdat Marketing, where he works with all types of clients from small-to-medium-sized businesses to Fortune 500 companies. In this role, Ross leverages his expertise to assess client needs, develop SEO strategies, manage projects, and support his team. He also handles analytics and reporting, delivering comprehensive reports to both clients and internal brands.

Originally from Leicester, England, Ross started working with computers after a gap year, eventually pursuing a full-time education in multimedia computing at De Montfort University. His introduction to SEO at a language travel agency marked the beginning of a fulfilling career.

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