Guide · Search
Mobile First Indexing: What It Means for Your Website
Mobile first indexing means Google uses the phone version of your page to index it and to rank it. If your phone page shows less than your desktop page, Google sees less. This guide explains what changed, what Google said to check, and a simple way to compare your two versions.
What mobile first indexing means
For years, Google's systems read the desktop version of a page. That could cause problems for people on phones when the two versions were very different.
Under mobile first indexing, Google uses the mobile version of the page for indexing and ranking. It is still one single index. Google says it does not keep a separate "mobile-first index".
This is about how Google gathers your content. It is not a new ranking bonus. Google said content gathered this way has no ranking advantage over content that is not yet gathered this way.
Sources: Google Search Central Blog, Rolling out mobile-first indexing, 26 March 2018
How it rolled out
Google announced on 26 March 2018 that it had started moving sites that follow its best practices. It told site owners through Search Console. Owners also saw a big rise in crawling from the smartphone version of Googlebot.
In July 2020, Google wrote that it had switched most crawled sites and had turned it on by default for all new sites. Its first plan was to move every site in September 2020. It then extended the date to the end of March 2021, because of the uncertain times.
So if you built your site before this change, check how it behaves on a phone. Do not assume it matches the desktop page.
Sources: Google Search Central Blog, Rolling out mobile-first indexing, 26 March 2018; Google Search Central Blog, Prepare for mobile-first indexing (with a little extra time), 22 July 2020
What Google asked site owners to check
Google said it would only get information from the mobile version. So Googlebot must be able to see the full content and all the resources on it. Its July 2020 post listed these checks:
- Robots meta tags. Use the same ones on mobile as on desktop. A noindex or nofollow on the mobile page only can stop Google indexing the page or following its links.
- Lazy loading. Do not hide main content behind a swipe, click or tap. Googlebot will not trigger those actions, so it will not see that content.
- Blocked files. If mobile pages use different URLs or hosts for files, make sure robots.txt does not block them. Blocking CSS files can stop Google rendering the page properly.
- Equal main content. If the mobile page has less content, Google advised making the main content equal. Only mobile content is used for indexing and ranking.
- Same headings. Use the same clear headings on both versions, with real heading tags.
Check your images and videos
Pictures and video need the same care. Google listed several points:
- Do not use tiny, low quality images on mobile. They may not be chosen for Google Images.
- Keep meaningful alt text. An alt text of just "Photo" does not help.
- If mobile uses different image URLs, you may see a short drop in Google Images traffic during the switch. Keep the desktop image URLs if you can.
- If desktop uses VideoObject structured data, add the same on mobile.
- Place videos and images where people can find them. A large ad at the top of a phone page can push a video far down.
A simple way to compare your two versions
You do not need special tools to start. Open one important page on your computer and on your phone. Then go down this table.
Check Pass if Main text The phone page has the same main content, not a shortened copy Headings The H1 and section headings match, as real heading tags Hidden content Nothing important sits behind a tap, swipe or button Robots tags Both versions carry the same robots meta tag Blocked files Your robots.txt does not block the CSS, images or scripts the phone page uses Images Images are clear, with alt text that describes them Video Video data is on both versions and the video is easy to find Fix the gaps in order of how much traffic the page earns. If an agency runs your site, ask them to walk you through each row. Google also said that a notice in Search Console shows when a site has been moved, so watch for it.
Sources: Google Search Central Blog, Rolling out mobile-first indexing, 26 March 2018; Google Search Central Blog, Prepare for mobile-first indexing (with a little extra time), 22 July 2020
Responsive sites and separate mobile sites
Google said sites that use responsive web design or dynamic serving are generally set for mobile first indexing. In both cases the content on the phone is usually the same as on the desktop.
Sites where the phone version uses different URLs or hosts need more care. Google's July 2020 post said to use the same robots meta tags, the same clear headings and equal main content on the phone version, and to make sure robots.txt does not block the phone version's files.
If you only have desktop content, Google said you would continue to be indexed. But phone users make up most of the audience, so a page that works well on a phone is the safer plan.
Sources: Google Search Central Blog, Rolling out mobile-first indexing, 26 March 2018; Google Search Central Blog, Prepare for mobile-first indexing (with a little extra time), 22 July 2020
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