How to Change a Theme in WordPress Safely (Plus How to Delete and Edit Themes)

Changing your WordPress theme is one of the fastest ways to refresh your site, fix a slow design or unlock new features. It is also one of the easiest ways to break a layout if you rush it. The good news: switching themes does not delete your posts, pages or images. This guide shows you how to change a theme in WordPress step by step, then covers how to delete themes in WordPress you no longer need and how to edit a WordPress theme without losing your changes on the next update.

What happens when you change a WordPress theme?

A theme controls presentation: layout, fonts, colors, templates, menu locations and widget areas. WordPress stores your actual content in the WordPress database, separate from the theme files. That is why a switch is safe for content but can disturb the look and some settings.

Two details worth knowing. First, WordPress saves each theme’s Customizer settings separately, so if you switch back to your old theme, those settings usually return. Second, your menus still exist after a switch; they are just unassigned from the new theme’s locations.

Before you switch: the pre-flight checklist

Ten minutes of preparation prevents most theme-change disasters. Do not skip these.

• Create a full backup of files and database with a plugin such as UpdraftPlus or through your host. Download a copy off the server.
• Copy your custom CSS. Go to Appearance → Customize → Additional CSS and paste it into a text file. See our guide to adding custom CSS in WordPress for where it should live afterwards.
• Save code added to theme files, especially functions.php snippets, analytics or pixel code in header.php, and anything inside your old theme’s options panel. A snippets plugin (see code snippets for WordPress) keeps code independent of any theme.
• Screenshot menus and widgets from Appearance → Menus and Appearance → Widgets so you can rebuild them quickly. If you are unsure how sidebars work, read WordPress sidebars and displaying a WordPress widget.
• Note shortcodes and page-builder content. If your old theme bundled its own shortcodes or builder, the new theme will not render them. Our shortcode fundamentals series explains why.
• Check requirements. Confirm your PHP version under Tools → Site Health → Info and that the new theme supports your page builder and plugins.
• Record a speed baseline with PageSpeed Insights so you can prove the new theme is faster.
• Pick the right theme. Browse free WordPress themes, the fastest WordPress themes or customizable WordPress themes, and check that it follows WordPress theme standards.

How to change a theme in WordPress (step by step)

Step 1: Put the site in maintenance mode (optional)

If you are switching directly on the live site, show visitors a friendly holding page with a plugin like WP Maintenance Mode. Skip this if you are working on staging.

Step 2: Install the new theme

1. In your dashboard, go to Appearance → Themes and click Add New Theme.
2. Search the official WordPress theme directory, or click Upload Theme to add a premium theme’s ZIP file.
3. Click Install. Do not delete your old theme yet; it is your instant fallback.

For a deeper walkthrough, including uploads and common install errors, see how to install a WordPress theme.

Step 3: Preview the theme with Live Preview

Back on Appearance → Themes, hover over the new theme and click Live Preview. Classic themes open in the Customizer; block themes open in the Site Editor. Click through your homepage, a post, a page and any special templates.

Step 4: Activate the theme

Happy with the preview? Click Activate. Open your homepage in a private browser window and confirm your posts, pages and media are all there.

Step 5: Reassign menus and rebuild widgets

• Go to Appearance → Menus → Manage Locations and assign your menus to the new theme’s locations.
• Open Appearance → Widgets. Widgets from the old theme that had no matching area sit under Inactive Widgets; drag them into the new areas.
• Block themes do not use classic widgets. Rebuild navigation and sidebars in Appearance → Editor.

Step 6: Re-add code, clear caches, test

Paste your saved CSS into Additional CSS, re-add tracking code, set your logo and favicon, and confirm Settings → Reading still points at the right homepage. Clear your caching plugin, server cache and CDN, then test forms, search and mobile views.

Other ways to switch: staging, FTP, database and WP-CLI

Change a theme on a staging site

Most managed hosts include one-click staging. You can also clone your site with a plugin such as WP Staging. Install, configure and test the new theme there, then push to live. If you prefer to practice first, you can also run a copy locally; see how to run WordPress on localhost.

Preview privately with Theme Switcha

The free Theme Switcha plugin lets you view a different theme in a separate tab while visitors still see the active theme. Enable it under Settings → Theme Switcha.

Change a theme via FTP when you cannot log in

1. Connect with an FTP client such as FileZilla or your host’s File Manager.
2. Open /wp-content/themes/ and upload the unzipped new theme folder.
3. To recover from a broken theme, rename the active theme’s folder (for example old-theme to old-theme-off). WordPress falls back to a default theme and your dashboard returns.
4. Log in and activate the new theme normally.

If the error was a 500 or white screen, our guides to the 500 internal server error and common WordPress errors will help. Locked out of your account instead? See WordPress admin password reset.

Change a theme in the database

The active theme is stored in the wp_options table in the template and stylesheet rows (and current_theme for the display name). Back up first, then set both values to the new theme’s exact folder name:

UPDATE wp_options
SET option_value = 'your-new-theme-folder'
WHERE option_name IN ('template', 'stylesheet');

Your table prefix may not be wp_. For related database edits, read how to change a URL in the WordPress database.

Change a theme with WP-CLI

wp theme list
wp theme install your-theme-slug --activate
wp theme activate your-previous-theme-slug   # instant rollback

After you switch: what to check

• Homepage, blog page, key landing pages, contact page and 404 page
• Header menu, footer menu, mobile menu and search
• Widgets, sidebars and footer columns
• Contact forms, newsletter forms and checkout (send real test submissions)
• Logo, favicon, fonts and colors under Appearance → Customize or Editor → Styles
• Analytics, pixels and any code you saved earlier
• Mobile, tablet and desktop layouts in more than one browser
• New page speed score compared with your baseline

Will changing your theme hurt SEO?

Your content, URLs and titles do not change, so rankings are rarely lost because of the switch itself. Problems come from what the theme does:

• Speed and Core Web Vitals. A heavier theme can slow pages down; a lean one can speed them up. Compare before and after.
• Structured data and meta tags. If your old theme output schema, Open Graph or title tags, move that job to your SEO plugin. Our beginner’s guide to WordPress on-page SEO covers the essentials.
• Heading structure. Make sure each page still has exactly one H1 and logical H2/H3 headings.
• Mobile layout. Check pages in Google’s mobile view and fix tap targets and overflowing content.
• Internal links and navigation. Menus that disappear can orphan pages from crawlers.

Afterwards, watch Google Search Console for new crawl errors or Core Web Vitals warnings over the next few weeks.

Changing themes on a WooCommerce store

Orders, products and customers are safe, but the shop’s templates come from the theme. Before going live, test the shop, product, cart, checkout and account pages on staging. If your old theme had custom files in a woocommerce folder, they will not carry over, and you may need to recreate them in a child theme. Starting fresh? Compare free WooCommerce themes and the best free WooCommerce themes, and check the WooCommerce Status report for outdated template warnings after the switch.

How to delete themes in WordPress

Unused themes add clutter and potential security risk, because an old, unmaintained theme can still contain vulnerable code even when inactive. Once your new theme is stable, remove the extras.

Delete a theme from the dashboard

1. Go to Appearance → Themes.
2. Click the thumbnail of the inactive theme you want to remove.
3. In the details window, click Delete (bottom-right corner).
4. Confirm the prompt.

Delete a theme via FTP or File Manager

Connect to your server, open /wp-content/themes/ and delete the theme’s folder. This is the way to remove a theme when the dashboard is unavailable.

Delete a theme with WP-CLI

wp theme delete theme-folder-name

How to edit a WordPress theme (the safe way)

1. Use the Customizer (classic themes)

Go to Appearance → Customize to change site identity, colors, typography, menus, widgets and homepage settings with a live preview. Highly flexible themes make this far easier; see our list of customizable WordPress themes.

2. Use the Site Editor (block themes)

For block themes, go to Appearance → Editor to edit templates, template parts, patterns and global Styles visually. If you are choosing a block-ready theme, start with Gutenberg-compatible themes.

3. Add small tweaks with Additional CSS

CSS added under Appearance → Customize → Additional CSS (or Editor → Styles in block themes) is stored in the database, so it survives theme updates. Example:

.site-title a { letter-spacing: .5px; }
.button, .wp-block-button__link { border-radius: 8px; }

4. Edit code with a child theme

If you must change template files or PHP, do it in a child theme. Edits made directly in the parent theme are erased the next time it updates. Create a folder in /wp-content/themes/ (for example my-child-theme) with two files.

style.css

/*
Theme Name: My Child Theme
Template: parent-theme-folder-name
Version: 1.0.0
*/

functions.php

<?php
add_action( 'wp_enqueue_scripts', function () {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
    wp_enqueue_style(
        'child-style',
        get_stylesheet_uri(),
        array( 'parent-style' ),
        wp_get_theme()->get( 'Version' )
    );
} );

Zip the folder, upload it under Appearance → Themes → Add New and activate it. To copy a template, place a file with the same name in the child theme and edit that copy. Prefer a no-code route? See the WordPress child theme plugin options. Block themes only need a style.css with a Template: line, and optionally a theme.json.

5. The built-in Theme File Editor (use with caution)

WordPress includes Appearance → Theme File Editor (under Tools on block themes). A single typo can trigger a fatal error and lock you out, and many hosts and security plugins disable it. If you use it, back up first and test on staging, and track changes with version control. For a deeper look at how themes are organized, see WordPress theme standards and the official Theme Handbook.

Troubleshooting common problems

When should you change your theme?

• The theme is no longer updated by its developer (a security risk).
• Your pages are slow even after optimization. Try one of the fastest WordPress themes.
• Mobile layouts are poor or fail Core Web Vitals.
• The theme lacks a feature you need or breaks on current WordPress or PHP versions.
• You are rebranding. Browse the latest WordPress themes or Elementor-ready themes for inspiration.
• You are building a new site from scratch; start with how to create a WordPress website and pick plugins from our must-have WordPress plugins.

Frequently asked questions

Conclusion

Changing a theme is safe when you treat it like a small project: back up, save your code, test on staging, switch, then verify menus, widgets, speed and SEO. Delete the themes you no longer use, and edit with the Customizer, Site Editor or a child theme so updates never wipe out your work. Follow the steps above and you can refresh your site’s design with confidence and without losing a single post.