Technical SEO guide
Half your visitors are on a phone, often on patchy mobile data. If your site takes five seconds to load, many of them are gone. Core Web Vitals are Google’s way of measuring that experience.
Short answer
Core Web Vitals are three Google measurements of real-user experience. Largest Contentful Paint (LCP) is how fast the main content loads, and should be under 2.5 seconds. Interaction to Next Paint (INP) is how quickly the page responds to taps, and should be under 200 milliseconds. Cumulative Layout Shift (CLS) is how much the page jumps around, and should be under 0.1. Test free with PageSpeed Insights. The biggest WordPress wins are smaller images, caching, a lighter theme and fewer plugins.
Key takeaways
- LCP should be under 2.5s, INP under 200ms, CLS under 0.1
- Test free with PageSpeed Insights and Search Console
- Images are the number one cause of slow sites
- Caching and good hosting fix a lot
- Speed helps conversions even more than rankings
The three Core Web Vitals
< 2.5s
LCP: how fast the main content appears
< 200ms
INP: how fast the page reacts when you tap
< 0.1
CLS: how little the page jumps around
Thresholds from Google’s Core Web Vitals documentation.
How to test your site (free)
02
Search Console
The “Core Web Vitals” report shows which groups of pages pass or fail for real users.
03
Your own phone
Open your site on 4G, not Wi-Fi. If it feels slow to you, it’s slow for customers.
The WordPress fixes that matter most
| Problem | Fix | Impact |
|---|---|---|
| Huge images | Resize, compress and serve WebP or AVIF | High |
| No caching | Use a caching plugin or host-level caching | High |
| Heavy page builder theme | Switch to a lightweight block theme | High |
| Too many plugins | Remove unused ones, avoid overlapping features | Medium |
| Slow hosting | Move to quality hosting with EU data centres | Medium–High |
| Layout jumps | Set image sizes, reserve space for banners and embeds | Fixes CLS |
| Chat widgets and tracking scripts | Load them later, remove what you don’t use | Fixes INP |
Does speed really affect rankings?
Google uses page experience signals including Core Web Vitals, but relevance and quality matter much more. A fast page with weak content won’t outrank a great page that’s a bit slower. The bigger win is usually conversions: faster pages lose fewer visitors before they call.
Go deeper See how we build fast WordPress websites →Speed, schema and tracking built in from day one
Frequently asked questions
What is a good PageSpeed score?
Aim for green Core Web Vitals (passing LCP, INP and CLS) rather than a perfect score. A mobile score of 70 to 90+ is good for most business sites.
Why is my mobile score lower than desktop?
PageSpeed Insights tests mobile using a slower simulated phone and network, so mobile scores are always lower.
Will changing hosting speed up my site?
Often, yes, especially if you’re on very cheap shared hosting. Fix images and caching first, because those are usually the biggest problems.
Is your site too slow?
We’ll test your key pages on mobile and send a prioritised list of speed fixes.