WP Core Web Vitals: download and installation
Upload the zip, activate it, turn off your other speed plugins and check a few pages in a private window. That takes about five minutes.
What do you need to install WP Core Web Vitals?
- WordPress 6.8 or newer and PHP 8.1 or newer. On older PHP the plugin switches itself off and the site keeps working.
- A writable
wp-contentfolder for the page cache and the CSS bundles. - Ideally a writable
wp-config.php, so the plugin can turn onWP_CACHEfor the Fast cache. If it can't, the settings page shows the line to add.
Step 1: download the zip
Download WP Core Web Vitals 8.0. It's free, without a license key.
Step 2: upload and activate the plugin
In your WordPress admin: Plugins, Add Plugin, then the Upload Plugin button at the top. Choose the zip and click Install Now.
WordPress unpacks the zip. Click Activate Plugin.
The settings are under Settings, WP Core Web Vitals, or behind the Settings link on the Plugins screen.
Updates come from corewebvitals.io and show up in Dashboard, Updates like any other plugin's.
Step 3: one optimizer at a time
Deactivate WP Rocket, LiteSpeed Cache, W3 Total Cache, WP Super Cache, Autoptimize, Perfmatters and the like. Turn off the "optimize" features of your host and page builder too, such as critical CSS or delaying scripts. Two optimizers on one page work against each other, and when something breaks you can't tell which one did it. A server cache from your host or Cloudflare in front of the site can stay.
Step 4: check the overview
Leave the defaults as they are: they're what I'd use on most sites. The overview shows what's on and what needs fixing, such as a Fast cache that isn't running.
Step 5: test your site logged out
Logged in, you get the unoptimized site. So open your home page, a post and, if you have a shop, a product page in a private window in Chrome. Click the menu and send a test form. Stay a few seconds on each page: your visit tells the plugin which image is the LCP element on that kind of page, at your screen size. Your visitors fill in the other screen sizes.
To see that visitors get the cached page, reload a page in that private window and view its source. The last line reads <!-- cached and optimized by wp-core-web-vitals plugin @ www.corewebvitals.io -->. If it isn't there, reload once more: the first load builds the cached copy, and the plugin builds it again after your visit reported the LCP element.
If something looks off, turn settings off one by one until it's gone. Troubleshooting lists the usual setting per symptom.
Step 6: measure your field data
Lighthouse shows one test load. Your Core Web Vitals come from your visitors, at p75 on mobile and desktop, in Search Console and CrUX. Search Console shows the last 28 days, so two weeks after you install the plugin half of what it shows is still the old site. Give it four weeks before you judge. Real user monitoring such as CoreDash shows your visitors' numbers per day, without that wait.
Upgrading from 7.x
Update as you would any plugin. Your settings, script rules and preloads move over on the first page load after the update, and the plugin stays off until that's done. Script rules that waited for the first interaction become Optimized: in 8.0 those scripts load once the page has loaded and the browser is idle. If the move fails, you get a notice in the admin: see troubleshooting.
You can also upload the 8.0 zip as in step 2. WordPress then shows the installed and the uploaded version side by side: click Replace current with uploaded.
