Google's page experience metrics LCP, INP and CLS: current thresholds, their effect on SEO and how to improve each one.
Core Web Vitals are the three metrics Google uses to measure how good a page's experience is for real users: loading speed, responsiveness and visual stability. An important change came in 2024 when INP replaced FID as the responsiveness metric. This guide brings together the metrics, thresholds and fixes that apply in 2026.
What Are Core Web Vitals
Core Web Vitals are based on real data collected from Chrome users, and each metric is assessed at the 75th percentile of visits. In other words, for a page to count as "good", at least three out of four visits must meet the threshold. Mobile and desktop are assessed separately.
The Three Metrics and Their Thresholds
| Metric | What it measures | Good | Needs improvement | Poor |
|---|---|---|---|---|
| LCP (Largest Contentful Paint) | When the largest content appears | 2.5 s or less | 2.5-4 s | Over 4 s |
| INP (Interaction to Next Paint) | Visual response time to interactions | 200 ms or less | 200-500 ms | Over 500 ms |
| CLS (Cumulative Layout Shift) | Unexpected layout shifts | 0.1 or less | 0.1-0.25 | Over 0.25 |
Why FID Was Retired and What INP Measures
FID (First Input Delay) only measured the delay of the visitor's first interaction, and most sites passed it easily. On 12 March 2024 Google removed FID from Core Web Vitals and replaced it with INP. INP observes all clicks, taps and keyboard interactions during a visit and reports one of the slowest. That makes it much better at capturing the "this site feels laggy" experience, and harder to pass. Content that still talks about FID is out of date.
How Core Web Vitals Affect SEO
Google says Core Web Vitals are among the page experience signals its ranking systems consider. It also stresses that a good page experience does not override relevant, high-quality content. In practice:
- If your content is weak, speed alone will not lift your rankings.
- Among pages of similar quality, a fast and smooth page can have an advantage.
- The real gain is with visitors: on pages that load quickly and do not lag, people stay longer, fill in forms and come back.
Where to Measure Core Web Vitals
- PageSpeed Insights: shows real user data and a lab test for a single page. See how to use PageSpeed Insights to read the report.
- Google Search Console: the Core Web Vitals report shows all your pages in groups of similar URLs, separately for mobile and desktop.
- Chrome DevTools: live metrics in the Performance panel show LCP, INP and CLS instantly while you use the page.
- Your own measurement: Google's open-source web-vitals library can send real user data to your own analytics.
Lab tests have no real user interaction, so they cannot measure INP; look at Total Blocking Time (TBT) instead.
How to Improve Each Metric
Improving LCP
- Cut server response time: page caching, an up-to-date PHP version, good hosting.
- Serve the LCP image as WebP or AVIF at the right size and prioritise it with
fetchpriority="high". - Never lazy-load images on the first screen.
- Reduce render-blocking CSS and JavaScript.
Improving INP
- Break long JavaScript tasks into smaller pieces so the browser can update the screen in between.
- Remove unused JavaScript and load heavy libraries only on the pages that need them.
- Avoid very large HTML structures (DOM) to reduce the work done on each interaction.
- Limit third-party code such as ads, chat and analytics.
Improving CLS
- Set
widthandheighton all images and videos. - Reserve space for ads, maps and embedded content.
- Do not insert banners or notices above existing content after it has loaded.
- Use
font-display: swapwith a fallback font of similar size so the font swap does not move text.
You will find all of these steps with example code in how to increase your PageSpeed score.
Mobile vs Desktop
The same page can do well on desktop and poorly on mobile, because phones have less processing power and slower connections. Google evaluates sites by their mobile version, so fix your mobile results first. We collected the mobile checklist in mobile-friendly website.
Conclusion
In 2026 Core Web Vitals consist of three metrics: LCP should be under 2.5 seconds, INP under 200 milliseconds and CLS under 0.1. Meeting these supports both the visitor experience and search visibility. Starting with a site designed for speed is always easier than fixing one later: see our Quick Website package, or our custom website with an admin panel service if you need custom features.