Buyer's guide · Site speed · Checked
How to check Core Web Vitals: free tools compared
Check your Core Web Vitals with PageSpeed Insights first: it's free, needs only a URL, and shows both real-user data from the Chrome UX Report (if your site has enough traffic) and a Lighthouse lab test. Then use Search Console's Core Web Vitals report to see which groups of pages fail, and Chrome DevTools' Performance panel to find what causes a slow LCP, a high INP or layout shift on your own machine. Google counts a page as good when, at the 75th percentile of real visits, LCP is 2.5 seconds or less, INP is 200 milliseconds or less and CLS is 0.1 or less. A green Lighthouse score alone doesn't mean you pass, because Google uses real-user data.
Disclosure: ChikuOS sells some of the options below, and they're labelled "ChikuOS". No vendor paid to be listed or placed, and we earn no commission or affiliate fee from any link on this page. Prices and features of other products are as listed on their own sites on 18 October 2026; follow the links to check current terms.
Free Core Web Vitals tools compared (as described in Google's documentation)
How we chose and ordered these: Tools with real-user (field) data come first, then lab tools, then the tool for debugging live on your own machine, then our paid fix. All the tools listed are free; what each shows is as Google's documentation describes it. How we compare.
| Tool | Data type | Price | What it shows | Good fit when |
|---|---|---|---|---|
| PageSpeed Insights | Real-user (CrUX) and lab (Lighthouse) | Free | LCP, INP, CLS and more from real Chrome users where available, plus a Lighthouse test with diagnostics | Your first check on any URL |
| Search Console Core Web Vitals report | Real-user | Free (needs a verified site) | Groups of similar URLs marked Good, Needs improvement or Poor, for mobile and desktop | Finding which templates or sections fail across the whole site |
| CrUX Vis | Real-user | Free | Chrome UX Report trends for an origin or URL over time | Seeing whether a fix moved real-user numbers |
| Lighthouse | Lab | Free (in Chrome DevTools or as a CLI) | A simulated load with a performance score and specific opportunities | Testing changes before they reach real users |
| Chrome DevTools Performance panel | Live, on your machine | Free | Live LCP, CLS and INP as you use the page, including soft navigations in single-page apps, plus a trace of what caused each | Debugging INP and layout shift in your own app |
| ChikuOS Core Web Vitals Fix Sprint | We find and fix the cause | $149, 3 business days after access | Diagnosis from field and lab data, fixes made in your code, before-and-after numbers | You know you're failing and want it fixed rather than diagnosed |
Lab data vs real-user data
Lighthouse runs one simulated page load on a fixed device and network. It's useful for testing, but Google's Core Web Vitals assessment uses field data: what real Chrome users experienced over the previous 28 days, from the Chrome UX Report. That's why a page can score green in Lighthouse and still fail in Search Console, and why a fix can take weeks to show up in field data. INP in particular depends on real interactions, which a lab page load doesn't capture well. Google's Web Vitals guidance sets the thresholds, and PageSpeed Insights' docs describe the 28-day field data window. If your site is new or small, there may not be enough traffic for field data yet; PageSpeed Insights will say so, and lab data is all you have.
The Web Vitals extension is gone
Many older guides tell you to install Google's Web Vitals Chrome extension. Google ended support for it in Chrome 132 and points users to the Performance panel in Chrome DevTools, which now shows live LCP, CLS and INP, including for single-page apps.
What to fix first
- Slow LCP: usually a large hero image, render-blocking fonts or scripts, or a slow server response. The Lighthouse diagnostics in PageSpeed Insights name the LCP element.
- High INP: long JavaScript tasks running when someone clicks or types. Record an interaction in the DevTools Performance panel to see which script blocks it.
- CLS: images or embeds without set dimensions, late-loading fonts, or banners inserted above content.
Apps built with AI tools often ship large JavaScript bundles and unoptimised images. If you want it fixed for you, our Core Web Vitals sprint is $149; our $49 audit includes a speed check alongside security and SEO.
FAQ
What is the best free Core Web Vitals checker?
PageSpeed Insights, because it shows real-user data from the Chrome UX Report and a Lighthouse lab test for any URL. For a whole site, use Search Console's Core Web Vitals report.
What are good Core Web Vitals scores?
Google counts a page as good when, at the 75th percentile of real visits, Largest Contentful Paint is 2.5 seconds or less, Interaction to Next Paint is 200 milliseconds or less and Cumulative Layout Shift is 0.1 or less.
Why is my Lighthouse score green but Core Web Vitals failing?
Lighthouse is a single simulated load, while Google's assessment uses 28 days of real-user data. Real visitors on slower phones and networks, and real interactions that affect INP, often produce worse numbers than a lab test.
How long does it take for Core Web Vitals fixes to show?
Field data covers the previous 28 days, so improvements show up gradually over about four weeks after the fix is live. Lab tools show the change immediately.
How much does it cost to check Core Web Vitals?
Nothing: PageSpeed Insights, Search Console, CrUX Vis, Lighthouse and Chrome DevTools are all free. Our fix sprint is $149, as listed on 18 October 2026.
How this guide was made: researched and drafted with AI assistance, then every price and claim was checked against the linked source on 18 October 2026. Editorial responsibility: ChikuOS. Spotted something out of date? Email hello@chikuos.com and we'll correct it.