Why Most WordPress Sites Fail Core Web Vitals — And How I Fix Them for Clients
Core Web Vitals have officially become one of the biggest ranking factors in Google’s Page Experience update. But here’s the wild part — most WordPress sites still fail Core Web Vitals badly, even if the design looks clean.
As someone who works on WordPress speed optimization projects daily, I see the same mistakes repeated across small business websites, agencies, and even premium themes.
Let me break down why WordPress sites fail Core Web Vitals — and how I fix these issues for my clients.
What Are Core Web Vitals (Quick Breakdown)
Core Web Vitals measure real-world user experience based on three metrics:
1️⃣ LCP — Largest Contentful Paint
How fast the main content loads.
2️⃣ FID / INP — Interaction Delay
How quickly a page reacts when users click.
3️⃣ CLS — Cumulative Layout Shift
How stable the layout stays while loading.
If any of these fail, your site:
❌ drops in rankings
❌ loses conversions
❌ gets lower user engagement
❌ Why Most WordPress Sites Fail Core Web Vitals
1. Bloated Themes and Page Builders
Most WordPress themes come loaded with features you never use. And when you stack Elementor, WPBakery, Divi, etc., the site becomes heavy AF.
Result:
Slow LCP, high INP, and terrible CLS.
2. Too Many Plugins (Plugin Overload)
I’ve seen sites with 40+ plugins… half of them doing nothing.
Each plugin adds:
⚠️ scripts
⚠️ CSS files
⚠️ database queries
This destroys Core Web Vitals.
3. No Proper Image Optimization
Big PNG/JPG images = slow LCP.
Clients upload 5MB images without even realizing it.
The site suffers instantly.
4. Render-Blocking JS & CSS
Common culprits:
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jQuery
-
sliders
-
animation libraries
-
embed scripts
-
unused theme files
If these load before page content → LCP fails.
5. Poor Hosting & No Server-Level Caching
Cheap hosting = slow TTFB.
Slow TTFB = slow everything.
This alone can cause a “Needs Improvement” score on all Vitals.
6. Layout Shifts Caused by Ads, Sliders & Fonts
CLS is usually bad because:
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images have no fixed dimensions
-
popups slide in
-
fonts swap
-
banners load late
This makes the page jump around.
🛠️ How I Fix Core Web Vitals for My Clients (My Exact Process)
1. Clean & Lightweight Theme Setup
I switch clients to:
✔️ Block Themes
✔️ GeneratePress
✔️ Astra
✔️ Kadence
Light, stable, fast.
If they want to stick with Elementor → I trim the bloat.
2. Remove Unnecessary Plugins
I audit the site and remove:
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duplicate functionality
-
inactive plugins
-
outdated scripts
Then replace them with light alternatives.
3. WebP + Next-Gen Image Optimization
I optimize images using:
✔️ WebP
✔️ AVIF
✔️ proper sizing
✔️ lazy loading
✔️ CDN delivery
Big improvement in LCP.
4. Minify, Delay & Defer JS/CSS
I use:
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Cloudflare
-
WP Rocket
-
Fast Velocity Minify
-
Perfmatters
Tricks I apply:
🔥 delay non-essential JS
🔥 remove unused CSS
🔥 inline critical CSS
🔥 defer scripts that block rendering
This improves both LCP & INP massively.
5. Server-Level Optimization
I move clients to hosts like:
-
Cloudways
-
Hostinger Premium
-
A2 Hosting Turbo
-
WPEngine
Then activate:
✔️ Redis caching
✔️ Brotli compression
✔️ HTTP/3
✔️ Full-page caching
TTFB drops like magic.
6. Fix CLS by Stabilizing Layout
I add:
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width/height attributes to images
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skeleton loaders
-
preloaded fonts
-
stable header structure
This eliminates those annoying jumps.
📈 Real Results I Usually Achieve for Clients
After optimization, most websites go from:
45–60 score → 90+ on desktop & 75–95 on mobile
And yes — this directly helps with:
🔹 higher Google rankings
🔹 better conversions
🔹 lower bounce rates
🔹 smoother user experience
Final Thoughts
Most WordPress sites don’t fail Core Web Vitals because WordPress is bad — they fail because they’re built carelessly.
Once optimized properly, WordPress becomes one of the fastest CMS platforms available.
If you want help improving your Core Web Vitals, feel free to reach out — I fix these issues for clients every day.