Core Web Vitals are three metrics Google uses to measure the real experience of people opening your site. LCP measures how long the main content takes to appear (the good threshold is 2.5 seconds), INP measures response to clicks and taps (200 milliseconds) and CLS measures how much the page shifts while loading (0.1). Thresholds are evaluated at the 75th percentile of real visits, split by mobile and desktop.
If your company has a website and you’ve heard “your Core Web Vitals are bad,” this article explains what that means, where to check, and what to fix first. If you’re looking for how to read a testing tool’s report, our PageSpeed Insights guide will serve you better. Here, the focus is the three metrics themselves.
What Are Core Web Vitals
Core Web Vitals are Google’s set of metrics for a page’s loading, interactivity and visual stability. According to the Google Search Central documentation, Google recommends that site owners achieve good values on all three, both for search performance and for the experience of the people who visit.
The key point is that the data comes from real people. It’s not a score from a lab test. It’s what Chrome users experienced when they opened your pages, aggregated over several weeks.
Official LCP, INP and CLS Thresholds
Each metric has three ranges, published by Google on web.dev. Keep this table handy, because it’s the one the tools use to color results green, orange or red.
| Metric | What it measures | Good | Needs improvement | Poor |
|---|---|---|---|---|
| LCP (Largest Contentful Paint) | Time until the largest element appears | up to 2.5 s | between 2.5 s and 4 s | over 4 s |
| INP (Interaction to Next Paint) | Response to clicks, taps and keystrokes | up to 200 ms | between 200 and 500 ms | over 500 ms |
| CLS (Cumulative Layout Shift) | How much the layout shifts unexpectedly | up to 0.1 | between 0.1 and 0.25 | above 0.25 |
A page only passes when all three metrics are in the good range at the 75th percentile. That means that out of every four visits, at least three need to stay within the limit. A fast visit from you, on fiber and a new computer, proves nothing.
LCP: how long until the main content appears
LCP is the time until the largest visible element on screen loads, usually the photo at the top or the big headline. For the visitor, it’s the moment the page “has arrived.”
Google breaks LCP into four parts that add up to the total time. Knowing which one is too long keeps you from fixing the wrong thing.
- Time to first byte. The server responds.
- Resource load delay. The browser takes a while to discover which image is the main one.
- Image download time. File size and format.
- Render delay. The image arrived, but something (like a script) holds back the display.
Google’s official guidance, in the LCP optimization guide, warns that optimizing one part can just push the time into another. Compressing the image won’t help if the element stays hidden until a script finishes loading.
On business websites, the most common causes are a huge hero photo, a server that is slow to respond, and the top image loading with lazy load, which delays exactly what should come first.
INP: does the page respond when you tap?
INP watches every click, tap and key press during the visit and usually reports the worst interaction. Google ignores the slowest one for every 50 interactions to filter out the effect of a one-off hiccup.
This metric replaced FID. According to web.dev itself, INP became a stable Core Web Vitals metric in 2024. If an old report still mentions FID, it’s outdated.
What makes INP poor on a business website:
- Too many third-party scripts, such as chat, pixels, maps and carousels.
- A menu or form that runs heavy code on every tap.
- Too many tags firing at once in Tag Manager. Our Google Tag Manager guide shows how to slim down the container.
What visitors feel is tapping the WhatsApp button and nothing happening for half a second.
CLS: why the page jumps while loading
CLS adds up unexpected shifts of visible elements. It’s the button that moves down right as you tap it, or the text that disappears behind a banner that pops in.
Google lists the typical causes in its CLS guide. Images and videos without set dimensions, fonts that change size as they load, and third-party ads or widgets that resize. The fix is usually cheap. Setting width and height on images and reserving space for banners and embeds solves most of it.
What business websites on Maps show
We measured mobile on a small sample to get a snapshot, not a market statistic. In October 2026, we collected the profiles Google Maps shows first in São Paulo, Rio de Janeiro and Belo Horizonte for each niche, and ran the mobile speed test on 8 websites from each.
| Niche (sample of 8 websites) | Median mobile LCP | Websites with LCP above 2.5 s |
|---|---|---|
| Dental clinic | 5.4 s | 100% |
| Aesthetics clinic | 5.05 s | 100% |
| Accounting | 5.15 s | 100% |
| Medical clinic | 9.65 s | 88% |
Across the 8 dental clinic websites we measured, none stayed within the good LCP threshold. For medical clinics, the median was over 9 seconds. With 8 sites per niche, the number doesn’t represent all of Brazil. It does show that the 2.5-second limit isn’t a comfortable one for most of the business sites your customers see first.
Where to measure: field data and lab data
There are two types of measurement, and mixing them up leads to pointless arguments with whoever built your site.
- Field data. Real visits from Chrome users. This is what Google uses. It appears in the Core Web Vitals report in Search Console and at the top of PageSpeed Insights.
- Lab data. A simulated test run on the spot with a standard device. Good for finding the culprit, but it’s not the score that counts.
The most direct path is to open the Core Web Vitals report in Search Console. It groups URLs by status (poor, needs improvement, good) and by metric, based on real data. A new or low-traffic site may not have enough field data, and then the lab is your only guide for a few weeks.
Do Core Web Vitals affect rankings?
They do, but they don’t decide rankings on their own. Google’s documentation on page experience says its ranking systems seek to reward content with a good page experience and that site owners shouldn’t focus on just one or two aspects. Core Web Vitals are one of the items on that list, alongside HTTPS, good display on mobile and no intrusive pop-ups.
In practice, a slow page with excellent content can still show up in results. What it loses is conversions. A visitor who waits 5 seconds on mobile goes back to search, and the ad or organic click you paid to get leaves without a quote request.
Where to start fixing
The order we use in audits, from what usually pays off most to least:
- Open the Search Console report and see which of the three metrics is flagged as a problem. Don’t touch the others.
- Find the LCP of your homepage and which element it is. If it’s an image, give it loading priority and remove lazy loading from that photo.
- Set width and height on all images and reserve space for banners, maps, and videos.
- List your third-party scripts and remove the ones nobody uses anymore.
- Retest after 28 days. Field data is aggregated and takes a while to reflect the fix.
This step-by-step is part of what we deliver in website optimization, along with the rest of technical SEO, which covers indexing, structure, and speed in the same plan.
Frequently asked questions
What are Core Web Vitals? They are three Google metrics that measure a visitor’s real experience on a page. LCP measures how fast the main content loads, INP measures the response to clicks and taps, and CLS measures visual stability.
What are the good thresholds for LCP, INP, and CLS? LCP up to 2.5 seconds, INP up to 200 milliseconds, and CLS up to 0.1, measured at the 75th percentile of real visits, according to Google.
Did INP replace FID? Yes. INP became a stable Core Web Vitals metric in 2024 and took the place of FID.
Do Core Web Vitals influence Google rankings? They are part of the page experience that ranking systems look to reward, but Google says not to focus on just one or two aspects. Relevant content still carries more weight.
Where can I see my site’s Core Web Vitals? In the Core Web Vitals report in Search Console, which uses real user data, and in PageSpeed Insights, which shows both field and lab data.
Why does Search Console show few or no URLs in the report? The report needs a minimum amount of real Chrome visits. Low-traffic sites may not appear, and in that case the lab test guides the fixes.
Want to know which metric your site is failing?
We review all three Core Web Vitals on your main pages and hand you a list of what to fix first. See how it works in website optimization for Google and AI and request the analysis.