Core Web Vitals are three measurements Google takes from real visitors' browsers to judge how a page feels: how fast the main content appears, how quickly the page responds when someone taps or clicks, and how much the layout jumps around while it loads. They feed into search rankings, but the bigger reason to care is simpler: slow, jumpy pages lose visitors before they find what they came for.
The three measurements
| Metric | What it measures | Good | Poor |
|---|---|---|---|
| Largest Contentful Paint (LCP) | How long until the main content, usually the hero image or headline, appears | 2.5 seconds or less | Over 4 seconds |
| Interaction to Next Paint (INP) | How quickly the page responds to clicks, taps, and typing | 200 milliseconds or less | Over 500 milliseconds |
| Cumulative Layout Shift (CLS) | How much content moves unexpectedly while loading | 0.1 or less | Over 0.25 |
A page passes when at least 75 percent of real visits over the previous 28 days meet the "good" mark.
Why the numbers disagree
Google PageSpeed Insights shows two kinds of results. Field data at the top comes from real Chrome users over 28 days; this is what Search Console reports and what counts. Lab data and the 0 to 100 score below come from one simulated visit on a slow phone connection. The lab score swings from run to run and is a diagnostic tool, not the target. A site can score 60 in the lab and pass Core Web Vitals in the field, and the field result is the one to manage.
Low-traffic pages may have no field data of their own; Google then uses the site-wide figures.
Usual causes, and who fixes them
| Cause | Hurts | Who fixes it |
|---|---|---|
| Oversized images, especially the hero image | LCP | Editors, with image sizes set by developers |
| Slow server response on uncached pages | LCP | Hosting: page caching, CDN, database and object caching |
| Too many third-party scripts: tag managers, chat, heatmaps, ad pixels | INP and LCP | Marketing and developers together |
| Heavy page builders and sliders | INP and LCP | Developers |
| Images and embeds without set dimensions | CLS | Developers, in the theme |
| Banners, cookie notices, or alerts that push content down | CLS | Developers: reserve the space or overlay it |
| Web fonts that swap late | CLS and LCP | Developers |
What editors can do today
- Resize images before uploading: a hero image rarely needs to be wider than about 2,000 pixels, and most content images far less
- Prefer modern formats such as WebP where your CMS supports them
- Embed video from a streaming service rather than uploading large files
- Avoid stacking several sliders, carousels, or embedded feeds on one page
- Ask before adding a new tracking or chat script, and remove ones from finished campaigns
Where to look
- Google Search Console, Core Web Vitals report: which groups of pages fail, and on which metric.
- PageSpeed Insights for one failing page: the field data first, then the lab diagnostics for clues.
- Your tag manager: list every script it loads and remove what nobody uses.
After a fix: why the report takes weeks
Field data covers the previous 28 days, so a fix released today shows up gradually as old visits drop out of the window. In Search Console, open the failing issue and use "Validate fix" once the change is live; Google then tracks the pages over the following weeks. A lab test in PageSpeed Insights confirms the change straight away, while the field data catches up.
Notes by platform
WordPress: performance plugins overlap with each other and with caching the host provides; running two can make things slower or break pages. Ask before adding one. Drupal: make sure the image styles in use produce sensibly sized images, and that CSS and JavaScript aggregation is on in production. Cascade: pages are static and served from a CDN, so LCP issues usually come from images and third-party scripts in templates.
How eWay handles performance
On sites eWay manages, page load time is monitored against a baseline, along with cache hit ratio and slow database queries, so a slowdown is noticed when it starts rather than when rankings move. Releases include a performance check before they go live. eWay tunes the hosting layers, page caching, CDN, and object caching, and can review a slow template or a heavy set of scripts with your team.
What to include in a support ticket
- The pages or page groups that fail, from Search Console
- Which metric fails: LCP, INP, or CLS
- Recent changes: new scripts, plugins or modules, a redesign
eWay customers can open a ticket in the support portal or email support@ewaycorp.com. Related reading: page caching and CDN behavior and object caching with Redis.
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