The WordPress Theme Review team is encouraging all theme authors to take notice of Google’s upcoming change to its ranking algorithm, which will be put in place at the end of April:

Starting April 21, we will be expanding our use of mobile-friendliness as a ranking signal. This change will affect mobile searches in all languages worldwide and will have a significant impact in our search results. Consequently, users will find it easier to get relevant, high quality search results that are optimized for their devices.

You can find out if your site is ready by testing it with the mobile-friendly testing tool created by Google. It will give you a rough idea of how the Googlebot views your pages.

Google Webmaster Tools has a new Mobile Usability Report that will also give you a more detailed breakdown of any mobile usability issues with your site.

Although Google hasn’t published an exact guide to how the new ranking algorithm will work, it provides a guide for mobile SEO. The documentation for the Principles of Site Design on Web Fundamentals is also a great resource with practical suggestions for making your site better for mobile users.

Google also created a mobile-friendliness guide specifically for WordPress users. It encourages site admins to update to the latest version of WordPress and to use a theme that that is mobile-friendly.

If you want to test your site on various mobile devices, the Google Chrome browser has a “mobile device emulation” feature that can be found under the “Developer Tools” menu.

Find a Responsive WordPress Theme

Out of the 3,000+ themes listed on in the official directory, filtering by “Responsive Layout” under “Features” currently returns only 947 themes. This doesn’t necessarily mean that 2/3 of themes hosted on WordPress.org are not responsive. These are simply the ones that have been tagged with “Responsive Layout.”

The Theme Review Team posted a notice about the update to encourage developers to examine their themes for mobile-readiness ahead of time. If your theme is not responsive, Emil Uzelac suggests adding responsive media queries:

Mobile-Friendly can be a Responsive design, but also an App that turns your theme into a “mobile version”. Since we don’t accept themes with mobile Apps because that would fall into a plugin territory, our choice is Responsive and media queries instead of browser sniffing tools. Now, for the mobile-friendliness, responsive media queries will be enough and that is the very basic to be qualified as “mobile-friendly”.

Not all WordPress.org theme developers will be willing to update their themes with a responsive layout, as some of them are abandoned and no longer maintained. If your theme is failing Google’s mobile friendly test, the most important change you can make is to update to a theme with a responsive layout. Even if site ranking and SEO are not important to your objectives, improving the experience for mobile users should be enough motivation to make the change.