A slow website rarely announces itself. Visitors simply leave, and the enquiry you never received does not show up in any report. Google's Core Web Vitals give you a practical way to measure how your pages feel to real people, and they are also a signal in search rankings. Passing them is less mysterious than it looks.
The three metrics in plain English
Core Web Vitals currently consist of three measurements, each with a "good" threshold that Google publishes.
- Largest Contentful Paint (LCP): how long the main content, usually a hero image or headline, takes to appear. Google considers 2.5 seconds or less good.
- Interaction to Next Paint (INP): how quickly the page responds when someone taps, clicks or types. Good is 200 milliseconds or less.
- Cumulative Layout Shift (CLS): how much the page jumps around while loading. Good is a score of 0.1 or lower.
Google assesses these using data from real Chrome users visiting your site, so your own fast office connection is not the benchmark.
Where to check your scores
Start with free tools:
- PageSpeed Insights shows field data from real visitors, if your site has enough traffic, plus a lab test with suggestions
- Google Search Console has a Core Web Vitals report grouping similar pages, which is ideal for spotting patterns
- Chrome DevTools lets developers record exactly what happens while a page loads
Pay most attention to field data and to mobile results. Mobile is where most sites struggle.
Fixing slow Largest Contentful Paint
LCP problems usually come from a heavy hero section or a slow server.
Common fixes
- Compress and resize hero images, and serve modern formats like WebP or AVIF
- Do not lazy-load the main image above the fold; load it with high priority instead
- Reduce server response time with caching, a better host or a content delivery network
- Remove render-blocking scripts and stylesheets that delay the first paint
- Avoid hero sliders that load several large images at once
Fixing slow Interaction to Next Paint
INP suffers when the browser is busy running JavaScript and cannot respond to the user. The usual causes are heavy themes, page builders and piles of third-party scripts such as chat widgets, tag managers and tracking pixels. Audit every script on the page and ask whether it still earns its place. Developers can break long tasks into smaller pieces and delay non-essential code until after the page is interactive.
Fixing Cumulative Layout Shift
Layout shift is the irritation of reaching for a button just as an advert pushes it down. To prevent it:
- Set width and height on images and videos so space is reserved
- Reserve space for adverts, embeds and cookie banners
- Load web fonts in a way that does not cause text to jump
- Avoid inserting content above existing content after the page has loaded
Platform-specific realities
On WordPress, speed often comes down to the theme, the number of plugins and the hosting. A lightweight theme, a good caching setup and fewer plugins can transform results. On Shopify, apps frequently inject scripts on every page, so removing unused apps and checking their leftover code is a quick win. Custom-built sites give the most control but still need discipline about images and scripts.
Keep it fast after launch
Many sites pass at launch and then slowly fail as new plugins, tracking codes and oversized images creep in. Make performance part of your publishing routine: compress images before upload, review new scripts before adding them and recheck Search Console every month.
FAQ
Do Core Web Vitals really affect rankings?
They are one of many ranking signals. Great content on a slower page can still rank, but when competing pages are similar, a better experience can help, and it certainly helps conversions.
Why is my score different each time I test?
Lab tests vary with network conditions and server load. Field data in Search Console is gathered over a longer period, so it is more stable and more meaningful.
Do I need a new website to pass?
Not always. Many sites pass after image optimisation, hosting improvements and script clean-up. A rebuild makes sense when the theme or platform itself is the bottleneck.
Next step
If your site is failing and you are not sure why, a performance audit will show where the time goes. Our web development and hosting teams handle this regularly, so ask us for a review.