What Are Core Web Vitals? LCP, INP and CLS Explained for Local Businesses

Core Web Vitals are three metrics Google uses to measure how a page feels to real visitors: how fast the main content loads, how quickly the page responds when someone taps or clicks, and how much the layout jumps around while it loads. They're called Largest Contentful Paint (LCP), Interaction to Next Paint (INP) and Cumulative Layout Shift (CLS). Google measures them from real Chrome users, not from a lab test.

This guide explains each metric and its threshold, how Core Web Vitals fit into Google's ranking systems, how to measure them, and the fixes that usually help on a WordPress site. Core Web Vitals are one part of technical SEO. For the bigger picture, see our SEO hub.

The Three Core Web Vitals and Their Thresholds

According to web.dev, the "good" thresholds are:

• Largest Contentful Paint (LCP) measures loading. It's the time until the largest image or block of text in the viewport appears. Good is 2.5 seconds or less.
• Interaction to Next Paint (INP) measures responsiveness. It looks at how long the page takes to visibly respond to clicks, taps and key presses throughout the visit. Good is 200 milliseconds or less.
• Cumulative Layout Shift (CLS) measures visual stability: how much content moves unexpectedly while the page loads. Good is 0.1 or less.

Google's PageSpeed Insights documentation lists the full ranges:

Metric	Good	Needs improvement	Poor
LCP	2.5 seconds or less	2.5 to 4 seconds	More than 4 seconds
INP	200 ms or less	200 to 500 ms	More than 500 ms
CLS	0.1 or less	0.1 to 0.25	More than 0.25

The 75th Percentile Rule

A page doesn't pass because it loaded fast once on your office computer. Web.dev says to measure at the 75th percentile of page loads, segmented across mobile and desktop. In plain terms, at least three out of four visits need to hit the "good" mark. Mobile is usually the harder test, because phones are slower and connections vary.

INP Replaced First Input Delay in March 2024

If you've read older articles, including the earlier version of this one, you'll see First Input Delay (FID) listed as a Core Web Vital. That changed on March 12, 2024, when INP officially replaced FID. FID only measured the delay before the first interaction was handled. INP looks at responsiveness across the whole visit, so it's a tougher and more useful measure. Search Console dropped FID the same day.

Are Core Web Vitals a Ranking Factor?

Partly, and it's worth being precise. Google's page experience documentation says "Core Web Vitals are used by our ranking systems." The same page answers the question of whether there's a single page experience signal: "There is no single signal. Our core ranking systems look at a variety of signals that align with overall page experience."

Google also says it "always seeks to show the most relevant content, even if the page experience is sub-par." So a slow page that answers the search best can still outrank a fast page that doesn't. Speed won't rescue weak content. Where Core Web Vitals help most is when your page is competing with others that are similarly relevant, and they help visitors either way: a page that loads quickly and holds still is easier to use and to call from.

Google's page experience guidance also asks whether pages are served securely over HTTPS, display well on mobile, avoid intrusive interstitials and don't bury the main content under ads. Those are part of a good page experience, but they aren't Core Web Vitals. Google notes that beyond Core Web Vitals, other page experience aspects don't directly help a site rank higher.

How to Measure Core Web Vitals

There are two kinds of data. Field data comes from real visitors. Lab data comes from a simulated test. Google's Core Web Vitals assessment uses field data, but lab tests are where you diagnose problems.

PageSpeed Insights

PageSpeed Insights is the fastest place to start. Enter a URL and it shows field data from the Chrome User Experience Report for the previous 28 days, when there's enough traffic, and runs a Lighthouse lab test with a list of suggested fixes. Check the mobile tab first.

The Search Console Core Web Vitals Report

The Core Web Vitals report in Google Search Console shows how your whole site performs. Its data comes from the Chrome User Experience Report. It groups URLs that have a similar experience, labels each group Good, Needs improvement or Poor, and splits results by mobile and desktop. This is the best way to see which templates are the problem: if every blog post fails LCP, the fix is usually in the post template, not each post.

Smaller sites often see "No data available." That means there isn't enough real-user data in the Chrome User Experience Report yet. In that case, rely on PageSpeed Insights lab results for your key pages.

The Chrome User Experience Report (CrUX)

CrUX is the public dataset of real-user measurements from Chrome. It's what powers the field data in PageSpeed Insights and Search Console. You don't need to use it directly, but it explains why a brand-new or low-traffic page may show no field data at all.

Lab Tools: Lighthouse and Chrome DevTools

Lighthouse, built into Chrome DevTools and PageSpeed Insights, tests a page in a simulated environment. It's useful for finding causes, such as which image is the LCP element. One limit: lab tools can't measure INP, because no real person is interacting with the page. Lighthouse reports Total Blocking Time (TBT) as a stand-in.

Common Core Web Vitals Fixes on WordPress Sites

Web.dev's guide to the most effective Core Web Vitals optimizations is the best reference. Here's how those recommendations usually translate on a small business WordPress site.

Improving LCP

• Compress and resize the hero image. Photos uploaded straight from a phone or camera are a common cause of a slow LCP.
• Don't lazy-load the main image. Web.dev recommends removing loading="lazy" from the LCP image, and adding fetchpriority="high" to it.
• Make the image discoverable in the HTML. Use a normal <img> element rather than a background image set by a slider script.
• Speed up the server response. Page caching and a CDN help serve pages faster to visitors.

Improving INP

• Remove plugins you don't use. Many plugins add JavaScript to every page, even where it isn't needed.
• Clean out your tag manager. Old tracking and chat scripts often stay installed long after anyone uses them.
• Watch heavy page builder widgets. Complex sliders, animations and popups can keep the browser busy, so taps feel slow.

Improving CLS

• Set width and height on images, so the browser reserves the space before the image arrives. WordPress usually adds these for images inserted in the editor, but custom theme code and some builders don't.
• Reserve space for embeds, banners and ads, such as review widgets, maps and cookie notices that push content down after the page appears.
• Avoid animations that move layout, and animate with CSS transforms instead.

Many fixes involve your theme or hosting, not just settings. If the report shows a whole group of URLs failing, start with the template they share.

Core Web Vitals and the Rest of Your SEO

Core Web Vitals sit alongside everything else that makes a page work. Images that are compressed and well labeled help both speed and on-page SEO. Clear, useful SEO content is still what earns the ranking, and clean header tags and internal links help visitors find their way once the page loads. For the local side, use our local SEO checklist.

Frequently Asked Questions

What are the three Core Web Vitals?

Largest Contentful Paint (LCP), which measures loading; Interaction to Next Paint (INP), which measures responsiveness; and Cumulative Layout Shift (CLS), which measures visual stability. Good scores are LCP of 2.5 seconds or less, INP of 200 milliseconds or less and CLS of 0.1 or less, at the 75th percentile of visits.

Is First Input Delay still a Core Web Vital?

No. Interaction to Next Paint replaced First Input Delay as a Core Web Vital on March 12, 2024. Older articles and reports that mention FID are out of date.

Do Core Web Vitals affect rankings?

Google says Core Web Vitals are used by its ranking systems, but there's no single page experience signal, and Google still shows the most relevant content even when page experience is weaker. Good scores help most when competing pages are similarly relevant.

Why does Search Console show no Core Web Vitals data for my site?

The report relies on real-user data from the Chrome User Experience Report. If your pages don't get enough Chrome traffic, there isn't enough data to report. Use PageSpeed Insights to run lab tests on your key pages instead.

Why is my PageSpeed Insights score different from Search Console?

PageSpeed Insights shows a lab test from Lighthouse alongside field data from real visitors, while Search Console shows field data only. The lab score changes from test to test. The field data, measured at the 75th percentile, is what the Core Web Vitals assessment uses.

Get Help With Core Web Vitals

Local Blitz has worked on SEO for local businesses since 2009, from offices in San Diego (Encinitas) and Indianapolis. We check your Core Web Vitals in Search Console and PageSpeed Insights, find what's slowing your key pages down, and fix it or work with your developer as part of our SEO work. There are no cookie-cutter packages, and plans are month-to-month. Book a free strategy call and we'll tell you what we see, even if the answer is that you can handle it yourself.