Core Web Vitals and SEO: What to Fix First
Core Web Vitals thresholds (LCP 2.5 s, INP 200 ms, CLS 0.1), what usually breaks them and the order to fix them, starting with key templates.
Quick answer
A page passes Core Web Vitals when at least 75% of real visits meet three thresholds: main content visible within 2.5 seconds (LCP), a reaction to taps within 200 milliseconds (INP) and a layout shift of 0.1 or less (CLS). Google recommends good scores and says they align with what its ranking systems reward, but relevant content still comes first. Fix the templates with the most traffic and enquiries first, usually starting with the largest image and heavy scripts.
Core Web Vitals are Google's three measures of how a page feels to real visitors: how fast the main content appears, how quickly the page reacts, and whether the layout jumps while loading.
Better scores usually mean fewer people leaving before they read, on pages that already rank.
Most teams know the three names but not what to fix first.
This guide gives the thresholds, the usual causes and an order of work tied to business impact.
Where speed fits in a full technical check is covered in our technical SEO audit.
What Are the Core Web Vitals Thresholds?
Google's web.dev documentation sets a good score for each metric, and a page passes when at least 75% of visits, measured separately on mobile and desktop, meet it.
| Metric | What it measures | Good score |
|---|---|---|
| LCP (Largest Contentful Paint) | How fast the main content appears | 2.5 seconds or less |
| INP (Interaction to Next Paint) | How fast the page reacts to a tap or click | 200 milliseconds or less |
| CLS (Cumulative Layout Shift) | How much the layout jumps while loading | 0.1 or less |
Do Core Web Vitals Affect Rankings?
Google recommends that site owners achieve good Core Web Vitals and says this, together with other page experience aspects, aligns with what its core ranking systems seek to reward.
It does not say good scores guarantee a high position, and a fast page with weak content will not outrank a slower page that answers the search much better.
The more reliable effect is on visitors: a page that appears quickly and does not jump keeps more of the people who arrive.
What Usually Causes Poor Scores?
Poor LCP often comes from oversized hero images, resources that block rendering and slow server response.
INP problems usually come from heavy JavaScript running when the visitor taps or types.
CLS problems are typically missing space reservations: images or embeds without dimensions, banners that load late and push content down, and web fonts that change size as they load.
Which Pages Should You Fix First?
Do not start with random pages.
Start with the templates that bring the most traffic and enquiries: the home page, the main service or product templates and the top landing pages.
A fix to one template improves every page built on it, which makes the work far more efficient than fixing pages one by one.
What Is the Order of Work?
Release changes in small steps and check both lab tests and real-visitor data, so you know which change made the difference.
- Compress and correctly size the first images on the page; prefer modern formats.
- Reduce CSS and JavaScript that block rendering, and defer scripts that are not needed straight away.
- Reserve space for images, embeds and anything that loads late.
- Break up long JavaScript tasks and remove third-party scripts you no longer need.
- Use a content delivery network (CDN) and caching to make server response steadier.
How Should You Measure and Report Progress?
Use the Core Web Vitals report in Search Console for groups of pages, PageSpeed Insights for single pages, and real-user monitoring where you have it.
Data from real visitors should drive decisions; lab tests are for diagnosing and for catching regressions before release.
Review the numbers monthly with whoever builds the site, and report the effect in business terms: fewer visitors leaving the page, more enquiries from the faster templates, steady positions on priority pages.
Core Web Vitals work is not about a perfect score. It is about removing the biggest friction for visitors on the pages that matter most to the business. If your site is slow on phones, our Web Design and Development service builds and fixes sites with speed measured on mobile.
Want to know which templates slow your site down? We review your Core Web Vitals and list the fixes in order of impact.
Get a free speed reviewFrequently asked questions
Do Core Web Vitals directly affect rankings?
Google says good Core Web Vitals align with what its ranking systems seek to reward, alongside other page experience aspects. They do not outweigh relevant content, but they affect whether visitors stay.
Which metric should we fix first?
The one that fails on your most valuable templates. On mobile that is most often LCP, usually because of a large first image.
Should we optimise for lab scores or field data?
Field data from real visitors should set priorities. Lab tools such as Lighthouse are for diagnosing problems and testing fixes before release.
How often should we review Core Web Vitals?
Monthly, and after every release that changes templates, scripts or how images are handled.
