What Happens When You Switch Your WordPress Theme

Ever wondered what happens when you switch a WordPress theme? This guide looks at how to swap to a new design with minimal disruption. It can be a daunting thought for inexperienced site owners, but don't worry. It's less hassle than you might think, as you're about to find out.

WordPress.org comes with three demo themes, the default being Twenty Nineteen. The other two are Twenty Seventeen and Twenty Sixteen. But there are thousands of others available, both free and premium. Most site owners prefer to switch to a design that best matches their project.

What Will You Lose when Switching Themes?

You won't lose uploaded image files, post or page content, or anything considered WordPress core. WordPress core is the foundational files needed for WordPress to function. However, you can expect to lose some or all theme-specific features. Even some plugins are theme-specific, as are sliders, shortcodes, post types & taxonomies.

Tip: Get to know your site. Make a note of what you're prepared to lose. Likewise, write down anything that MUST be part of the new look and whether you can add it/them back.

Golden Rule #1 Back Up

Never switch to a new WP theme until you've done a full backup of your site. Your database holds everything, including posts, pages, comments, links, and so on. A full backup of your WordPress website or blog includes the database and all files. Having a full copy of your site lets you continue with confidence. You can then quickly restore things if something goes wrong.

Golden Rule #2 Preview

A web developer may prefer to test a new theme in a staging environment. However, it's unnecessary for a non-custom theme swap if you follow the basic rules outlined in this guide.

The best way forward is to try before you make the switch. Just because a theme sounds great, that doesn't mean it's the ideal choice for your site. WordPress lets you preview installed themes without activating them. All you do to take control is click the Live Preview button. We'll get to that later, but first, let's look at what changes to expect with a new theme.

WordPress themes and Custom menus

Your custom menus should still be there with a new active theme, but they might have moved. If they're in a different location, you may be able to reposition them if you want to.

Go to Appearance => Menus and check the menu location options.

Widgets and widget-friendly sidebars

Your widgets should still be there, albeit inactive. That's because the widget areas and names differ between themes. You can reassign them to the sidebars of the new WordPress theme in most cases. However, any theme-specific widgets will most likely disappear.   

Go to Appearance => Widgets to see if you can drag-n-drop inactive widgets back into place.

Tip: Some themes create specific widgets that may replace yours. The way to keep tabs on what you have is to write down all essential widgets before the switch.

Theme settings

The changing layout, functions, and options can differ significantly between themes. Your current settings will disappear with a theme switch. The new one might have more customisations than you need, but it could also lack some controls that you want.

Here's a side-by-side comparison between two different themes to illustrate.

Make a manual checklist of the differences and note anything that's missing from the new theme. Pay particular attention to areas like the header, background image, logos, and so on.

Note: Any missing media files will still be available from your Media Library. However, the autogenerated featured image and thumbnail sizes may differ between themes.


Most plugins are created to work with WordPress versions and are independent of themes. The only time you might lose a plugin or its functionality is if it's theme-specific.

Search Engine Optimisation (SEO)

Do you use an SEO plugin like All in One SEO or Yoast SEO? If yes—and you have many posts and pages—you'll have a lot of saved SEO data. That includes things like keywords, meta titles, and unique descriptions for each published post or page.

Your SEO data could be missing if the new theme has its own built-in SEO settings. Don't worry. It's quite possible to transfer your SEO data from the old theme to the new one. The simplest method is to use the SEO Data Transporter plugin by StudioPress.

Custom scripts

Custom scripts can get lost with theme switches. The most widely used of these is Google's analytics tracking code. The new theme might have an input box where you can paste custom scripts. If not, there are lightweight plugins that can do this for you in an instant.

Theme-specific shortcodes

Shortcodes offer site owners a quick way to add functionality to posts and widgets. Theme-specific shortcodes include things like sliders, galleries, column layouts, buttons, etc. Switching themes disables theme-specific shortcodes.

Please be aware that themes like DIVI extensively use shortcodes, making switching theme a very time-consuming task.  When you switch from DIVI, your content will be garbled and replaced with shortcodes.  For this reason, I don't recommend you switch from DIVI unless you know what you are doing.  For this reason, DIVI is one of the only themes I do not recommend.

Try Before You Change Your WordPress Theme

You now know what to expect when switching themes. It doesn't have to be a gamble if you take time to explore any gains, losses, and future potential of the new design. Having a simple checklist of must-haves, would-likes, and expectations is a good place to start.

It pays to preview your WordPress website or blog before you activate any new theme. Using Live Preview lets you try the theme settings without affecting the live site.

Log in to your WP Dashboard.

Go to Appearance => Themes from the side menu.

Locate the theme you're interested in or install a new one, but DON'T activate it.

Hover the mouse over the theme cover and click the Details & Preview link to learn more.

You're now at the details screen, where you can read about the theme in the left-side column. There's also a live theme demo on the right-side.

Take some time to navigate the live demo and view other parts of the template.

Click X when you're done to close the Details & Preview area and return to the themes screen.

Now click the Live Preview button to see how your site looks with the new theme.

You can now safely navigate your website or blog from the right-side Live View panel.

Make notes of what you do like, don't like, and the customisation options in the left-side column.

Be sure to visit a few individual posts, pages, and archives to get a feel for the theme.

Ask yourself these two questions as you explore the new design:

  1. How easy is it to make essential changes if you need to? 
  2. Do the settings offer everything you need? 

If you made a list earlier (recommended), refer to it as you navigate the Live Preview.

Set aside some time if you decide to go with the new theme. That way, there's less stress as you test, tweak, and fix any minor hiccups along the way.

Want to Learn WordPress?

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