Core Web Vitals on WordPress: A Step-by-Step Guide That Actually Fixes Performance Issues

Core Web Vitals are Google’s way of checking how easy and pleasant your website is to use. They look at things like how fast your site loads, how quickly it responds when someone clicks, and whether things move around on the page while it’s loading. If your site feels slow or frustrating, people are more likely to leave—and Google may show your site lower in search results. But if your site feels smooth and easy to use, more visitors will stick around, trust you, and are more likely to book or reach out. It’s all about giving your visitors a better experience and helping your business get found online.

Core Web Vitals (CWV) are comprised of three primary metrics that Google uses to measure real world User Experience:

• LCP (Largest Contentful Paint) – how quickly the main content loads
• INP (Interaction to Next Paint) – how responsive the page feels to user interaction
• CLS (Cumulative Layout Shift) – how visually stable the page is during loading

The thresholds for a “Good” experience are:

• LCP ≤ 2.5s
• INP ≤ 200ms
• CLS ≤ 0.1

Google announced in March 2024 that INP has officially replaced FID (First Input Delay) as a Core Web Vital. These numbers are not just technical terms but have a direct impact on your SEO ranking and conversion rates.

How to Measure Core Web Vitals on WordPress

Before you can optimize, you’ll need to take an accurate measurement. There are two types of data:

• Field data – collected from real users (CrUX). Google uses this for search rankings.
• Lab data – captured in controlled testing conditions (Lighthouse). It is good for diagnostics, but has no relevance for SEO.

Tools to Use:

• Google Search Console → Core Web Vitals. Gives both mobile and desktop reports based on real user data. Drill down into a group of URLs → click on a URL → view detailed PageSpeed Insights reports.
• PageSpeed Insights. Lists “Opportunities” and further detailed recommendations for each page.
• Site Kit by Google plugin. Aggregates Search Console, Analytics, and PSI reports directly in your WordPress dashboard.
• Third-party SEO tools (WebSite Auditor, Semrush, etc.). Good for batch-checking a lot of URLs at once.

NOTE: Core Web Vitals reports in Search Console are based on a rolling 28-day window. As time progresses, changes will be gradual as old data is replaced by new user session data.

The 6 Steps to Fix Core Web Vitals on WordPress

These are the changes having the most impact. Follow these in order as they build upon each other.

Step 1. Improve LCP (Largest Contentful Paint)

Goal: LCP ≤ 2.5s.

• Make the hero lighter. Swap out heavy sliders or banners for optimized WebP/AVIF images or simple CSS gradients. An example:

<img src="/img/hero.webp" width="1280" height="720" fetchpriority="high" loading="eager" decoding="async" alt="Hero banner">

• Preload fonts and critical resources.

<link rel="preload" href="/fonts/inter.woff2" as="font" type="font/woff2" crossorigin>

• Create critical CSS. Use plugins like WP Rocket or LiteSpeed Cache to inline above-the-fold CSS.
• Minimize server response time (TTFB). Enable full page caching, link a CDN (Cloudflare, QUIC.cloud), run on PHP 8.2+, and consider moving to managed WordPress hosting if shared hosting is slow.
• Recommended plugins: WP Rocket, LiteSpeed Cache, Autoptimize.

Step 2. Reduce CLS (Cumulative Layout Shift)

Target: CLS ≤ 0.1

• Define width/height or use CSS aspect-ratio for images.
• Your layout should reserve space for ads, widgets, or iframes so they do not “push” content down.
• Use font-display: swap; and preload builtin fonts to avoid a flash of invisible text.
• Do not insert new elements at the top of the user’s viewport post load (ex: banners, popups).

Step 3. Optimize INP (Interaction to Next Paint)

Target: INP ≤ 200ms.

• Break down long-running Javascript tasks (>50ms). Chunk heavy scripts and use requestIdleCallback and async functions to do this.
• Defer or delay non-essential javascript.

<script src="/js/gallery.js" defer></script>

• Solutions like WP Rocket (Delay JS Execution) or Perfmatters make it super easy to manage this.
• Use passive event listeners for scroll/touch events:

window.addEventListener('touchstart', onTouch, { passive: true });

• Reduce third-party scripts. Remove unnecessary widgets, animations, or tracking tags.

Step 4. Mass-Optimize Images

• Convert images and iframes to WebP/AVIF and keep originals as fallbacks.
• Lazy load images and iframes.
• Use plugins Imagify, ShortPixel, and Smush for image compression and WebP generation.

Step 5. Clean Up Themes & Plugins

• Themes and builders can add heavy bloat to load times. Audit your theme and remove large sliders/mega menus, if possible.
• Remove or replace unneeded plugins. Use Perfmatters Script Manager or Asset CleanUp to disable all scripts/styles on pages (if not needed).
• If your host supports it, enable Object Cache (Redis). Object cache speeds up database queries.

Step 6. Validate, Monitor & Repeat

• Perform tests with PageSpeed Insights on the most important templates (home, blog, product pages).
• Recheck Search Console → Core Web Vitals after 1–2 weeks, keep in mind the 28 days.
• Maintain gains: create a publishing checklist (optimize images, avoid above-the-fold bloat, test mobile).

Quick Real-World Examples

• Problem: PSI indicates “Reduce initial server response time.”
  Solution: Add page caching, enable CDN, upgrade PHP, or move to managed hosting.
• Problem: Search Console shows CLS issue: greater than 0.1.
  Solution: Add fixed image dimensions, reserve ad/widget space, preload fonts.
• Problem: High INP on content heavy pages.
  Solution: Defer third-party scripts, break long JS tasks, disable unused plugins.

FAQs

Do I need a perfect 100/100 score?

Absolutely not. You just need to outperform your competitors—especially the ones showing up next to you in search results.

That said, at Hey Reliable, we aim higher. We guarantee scores above 90% across all categories—Performance, Best Practices, Accessibility, and SEO—because those results translate into real business outcomes: faster sites, higher rankings, lower bounce rates, and better conversion. Whether you’re a luxury travel agency, an e-commerce brand, or a marketing team, these improvements make your site feel effortless to use—and that’s what keeps visitors engaged.

Below are recent before-and-after scores we’ve achieved for a variety of clients across different industries:

Why do PSI and Search Console results differ?

PSI reports lab data; Search Console only reports field data (real users). It’s expected to see differences.

When will my improvements show in SEO?

Typically, in a few weeks, after previous sessions are improved on and better field data replaces in Google’s 28-day dataset.

Final Thoughts

Core Web Vitals is not simply an obsession over vanity scores – it is about improving the performance of your WordPress site to make it speedier, more reliable, and easier to use. All of which means more rankings, less bounce, and more conversions. First target the low-hanging fruit (that’s optimizing images, cleaning up the hero, enabling caching) and then hit the harder targets (deferring JS, upgrading hosting, reducing plugins).

Need Expert Help?

If you’d prefer to have professionals do all of this for you, our team at Hey Reliable consists of WordPress developers and Core Web Vitals experts and we can take care of it all for you. From taking a full site audit (complete with recommendations), installing plugins and setting them up, setting up a CDN, and cleaning up themes/code – we fix performance bottlenecks and we confirm improvements directly in Google Search Console.

The Author

Mary Marnell

Mary Marnell is Managing Partner at Hey Reliable, where she’s been hands-on with every part of the business since 2017. From working directly with clients to collaborating with developers and reviewing front-end code, Mary moves fluidly bet...