When I posted the tips you should consider before changing WordPress themes, i got asked a lot if changing the WordPress theme affects SEO, so let’s answer them here so we all can learn.
One of the implications you should take into account when choosing the new theme is the effect it could have for the SEO of your site.
Well…does it?

Does changing your WordPress theme affect SEO?
Yes, generally yes, WordPress themes can affect your SEO ranking to a great extent. Themes can affect negatively important SEO factors such as stability, speed, content, metadata and indexing of your website. However, when done right, changing themes can maintain or even improve your SEO ranking.
By changing the theme of a website, all factors can be influenced positively or negatively. It can also improve some features and reduce the effect of others. You need to make sure that everything works and make any test needed, because of the potential impact these factors can have on your SEO.
If we isolate these factors, we can better determine exactly how they can affect your website.
How does changing the theme affect your SEO?

For most people, a WordPress theme is simply a redesign of their pages.
However, at its core, a theme can change many more essential background details. Many of these details can play a role in how Google crawls and views your pages.
The following factors can influence your SEO both positively and negatively when changing the theme of your website.
Increase or decrease the loading speed of your site

Your theme determines how many scripts and assets your website loads when a visitor arrives. Therefore, changing your existing theme can either speed up or slow down your website.
As a general rule, you should look for a theme that is as fast as possible from the start.
This is because once you implement a theme, your plugins and customizations will further increase the page load time. There may even be incompatibilities(with plugins etc) that make the new theme significantly slower than your current theme in some extreme cases.
Upgrades or downgrades the design and user experience
Your WordPress theme represents one of the most critical factors of a modern website, its design. Naturally, using a theme that you’re happy with makes your experience and job more enjoyable.
However, web design is even more important for other people that are not you: your users/clients/viewers/readers. User experience is crucial to your conversion rates and SEO, and a theme can either improve or ruin that experience.
When you change the theme of a website, almost all users are initially confused until they get used to it. This is subjective and cannot be judged beforehand.
However, there are also many objective factors by which you can effectively judge the theme before deciding to implement it: Tools you offer, where are placed the main attractive aspects of your website, easy to read and use, easy to find the different elements…
Secretly modifying your SEO metadata
Your theme can also affect the way robots like Google see your design. This is because different themes may contain or edit additional metadata that Google uses to better understand your pages.
SEO metadata, such as the page title and meta description
, are not direct ranking factors, as they alone do not determine how you rank. However, they are an indirect factor that influences the user’s decision to click on your website when it appears in the search engine results.
If you currently rank well for a keyword, changing the page title, even by accident, can cost you rankings in the long run.
Add, change or delete structured data
Like the previous tip, different themes bring different structured data configurations.
Structured data, also known as Schema, is a type of metadata that search engines like Google use to better understand the content of a page. They also use that markup to display characteristics of the content on the search results page.
If your current theme tags all of your articles with the proper Schema, you could potentially lose it when you switch themes.
Structured data alone, again, is not a decisive ranking factor. However, like many things in SEO, it is a piece of the puzzle that can give you a slight boost.
Changing the format of your content, headers, etc.

Different issues can also affect the formatting of essential HTML elements. One of the most common cases is the duplication of heading tags.
Although this is not a decisive problem, it can confuse both Google and the reader, as both expect a uniform and correct hierarchy of elements.
This can be a problem if, for example, your current theme requires you to add H1 tags manually or add them in duplicate.
New themes may have that functionality built-in, which means you’ll have to revisit old pages to remove the redundant element.
Modify default image sizes and their indexing
One of the elements that themes can influence from a content point of view is images.
By default, WordPress makes different versions of your images when you upload them. It does this so that you can use the best image size for each task.
For example, you don’t need to upload a full-size HD image to your blog’s archive page. Doing this will only slow down your website.
Instead, WordPress shrinks the image and serves it up, making it much lighter for users to download when browsing.
However, some themes may change the default processing of images. While it’s unlikely that your new theme will replace the photos in your blog posts, there is some chance of that happening.
If that happens, you can lose both image SEO and alt
tags. In addition, it can also make your posts less relevant overall – and this can hurt your SEO.
Affect your site’s search functionality
Some themes may remove search functionality from your site. Before implementing the new one, make sure everything works.
If you currently have a search bar, check to see if the new theme includes it as well. If you don’t currently have it, implementing it along with your new theme is an excellent idea.
This will allow users to better navigate your site and help you keep track of what visitors are interested in through site search tracking.
And these are some, but not all, of the SEO factors that can be affected by changing WordPress themes. If you have experienced any other factors that affect SEO when changing WordPress themes, don’t hesitate to let us know in the comments so we can learn from your experience as well.