1. Source
Real-user field data from the Chrome User Experience report. The result identifies where its evidence came from.
Free tool, no account required
Free Core Web Vitals Checker (LCP, INP, CLS)
The Novaverb Core Web Vitals checker reads 75th-percentile real-user LCP, INP and CLS for an address from the Chrome User Experience report and shows whether every available metric is within the published good thresholds.
Also known as: CWV, LCP, INP, CLS, Core Web Vitals
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Definition
What is a Core Web Vitals checker?
A Core Web Vitals checker reports how real visitors experienced a page on three metrics: loading, responsiveness and visual stability. The Novaverb Core Web Vitals Checker reads 75th-percentile field data for LCP, INP and CLS from the Chrome User Experience report and states whether the address passes the published good thresholds.
Scope
What does the Core Web Vitals checker check?
The Core Web Vitals checker checks three field metrics for the submitted address: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness and Cumulative Layout Shift for visual stability. Each one is read at the 75th percentile for phone and for desktop, with the share of good, needs-improvement and poor visits.
Who it is for
Who is the Core Web Vitals checker for?
The Core Web Vitals checker is for people who need real-user evidence instead of a simulation. An SEO specialist uses it to see whether a template passes in the field, a developer uses it to confirm that a lab fix reached actual visitors, and a site owner uses it to compare phone and desktop experience.
Why it matters
Why use a Core Web Vitals checker?
A Core Web Vitals checker shows a page experience problem that a lab test on one simulated device can miss. Field data reflects the devices and networks visitors really use, so a page that scores well in a controlled run can still be slow or unstable for a large share of its audience on phones.
Method
How does the Core Web Vitals checker work?
The Core Web Vitals checker works in three steps. The address is normalized, then 75th-percentile real-user field data is read from the Chrome User Experience report for phone and desktop. LCP, INP and CLS are rated against the official thresholds, unchanged. Where URL-level data is missing, the tool falls back to origin level and labels the scope.
- We normalize the address and read 75th-percentile real-user field data from the Chrome UX Report (CrUX).
- We report LCP, INP and CLS against the official Core Web Vitals thresholds.
- We fall back from URL-level to origin-level data and label which scope the numbers came from.
Input
What do you enter into the Core Web Vitals checker?
Enter the page address you care about into the Core Web Vitals checker. A bare domain, or a URL with or without www, is normalized. A popular page or the origin returns the richest data. A private host is refused, and a brand-new or low-traffic page returns no field data instead of an estimate.
Use it like this
yourdomain.comAny address form works - a URL with real traffic has the richest field data. http or https, with or without www, a bare domain or a full path - we normalize it for you.https://www.yourdomain.com/The origin or a popular page is ideal; we fall back origin-level if a URL has no sample.Avoid this
Reading 'no field data' as an errorA brand-new or low-traffic page simply has no Chrome UX Report sample, so we honestly say so instead of guessing.Result
What does a Core Web Vitals checker report contain?
A Core Web Vitals checker report contains a phone tab and a desktop tab. Each shows a passes, does not pass or assessment incomplete verdict, the scope the numbers came from, the collection period, and a card per metric with its 75th-percentile value, its rating and a distribution bar of good, needs-improvement and poor visits.
Reading it
How do you read a Core Web Vitals check result?
Read a Core Web Vitals check result scope first. If the label says whole-site origin data, the numbers describe the site, not the single page you entered. Then read each rating: the assessment passes only when LCP, INP and CLS are all good, and a missing core metric leaves the assessment incomplete.
Core Web Vitals explained
Field data is how Google actually judges page experience
Core Web Vitals measure loading (LCP), interactivity (INP) and visual stability (CLS) from real Chrome users - not a lab simulation. Google uses this field data as a ranking signal, so the p75 value is what matters, not a one-off lab score.
The three metrics
- LCP - Largest Contentful Paint: how long the main content takes to render. The result shows your p75 against Google's good and poor thresholds.
- INP - Interaction to Next Paint: how quickly the page responds to taps and clicks across the whole visit. It replaced FID in 2024; the result shows your p75 against Google's thresholds.
- CLS - Cumulative Layout Shift: how much the layout moves while the page loads. The result shows your p75 against Google's thresholds.
URL vs origin data
Low-traffic URLs may not have their own field data. In that case this tool falls back to origin (whole-site) data, which is clearly labeled - it reflects the site overall, not that single page.
Source
Where does the Core Web Vitals checker get its data?
The Core Web Vitals checker gets its data from the Chrome User Experience report, a dataset of real-user field measurements from Chrome. The values cover the trailing 28 days and are read at the 75th percentile. Nothing is measured at the moment you run the check, so a page without enough traffic has no record to read.
Limits
What does the Core Web Vitals checker not tell you?
The Core Web Vitals checker does not tell you why a metric is slow or how the page performs right now. The tool reads field data collected over the trailing 28 days for pages with enough Chrome traffic. Low-traffic pages fall back to origin-level data or report no field data, and none of it is a lab test.
Evidence
What does a Core Web Vitals check result prove?
A Core Web Vitals check result proves what real Chrome users experienced on the address during the collection window, at the 75th percentile. The result does not prove anything about visitors outside that dataset, about a change shipped yesterday, or about rankings. No field data means too few samples, not a slow page.
2. Boundary
This reads real-user field data collected over the trailing 28 days for pages with enough Chrome traffic. Low-traffic pages fall back to origin-level data or report no field data - this is not a lab test.
3. Next action
Use the finding to verify a problem, then connect a workspace when you need history, monitoring, or site-wide analysis.
Standards
Which standards does the Core Web Vitals checker apply?
The Core Web Vitals checker applies the published Core Web Vitals definitions and reads the Chrome User Experience report. The definitions supply the three metrics and their good and poor thresholds, which the report applies unchanged. The Chrome dataset supplies the 75th-percentile field values. The tool makes no ranking prediction from a passing or failing result.
GoogleCore Web Vitals
web.dev Web Vitals
Reports LCP, INP and CLS against the official Core Web Vitals thresholds.
Read the specificationGoogleCrUX
Chrome UX Report
Reads 75th-percentile real-user field data from the Chrome UX Report.
Read the specificationWe list a standard only where this tool genuinely reads or measures against it. Where a signal is outside a live check, the result says so instead of implying coverage.
Verification
How can you verify a Core Web Vitals check result yourself?
Verify a Core Web Vitals check result by looking up the same URL or origin and the same device type in the public Chrome User Experience report and comparing the 75th-percentile values and the collection period. Check the scope as well, because an origin record and a URL record for the same site can differ.
Example
What does a typical Core Web Vitals checker finding look like?
A typical Core Web Vitals checker finding is a page that passes on desktop and does not pass on phone, with LCP rated needs improvement while INP and CLS are good. The distribution bar shows a visible share of slower visits, which points the work at the largest element and the server response behind it.
Cost
Is the Core Web Vitals checker free?
The Core Web Vitals checker is free and needs no account to read both device tabs for an address. An account is needed for the parts a single field snapshot cannot give: saved evidence, a trend of LCP, INP and CLS over time, and moving a failing metric into a task that is rechecked.
In a workspace
What does a Novaverb workspace add to the Core Web Vitals checker?
A Novaverb workspace adds saved evidence and monitoring over time to the Core Web Vitals checker. Visitor Behavior continues the job with field data from your own traffic: it reports LCP, INP and CLS measured on participating visitors' devices for pages that carry the installed tag, and pages without observations stay unavailable.
When to go further
When is a free Core Web Vitals check not enough?
A free Core Web Vitals check is not enough when the page has too little Chrome traffic to hold its own record, when you need to know whether a release changed the numbers, or when every template of a site must be judged. Those cases need recurring measurement and page-level data from your own visitors.
Next step
What should you do after running the Core Web Vitals checker?
After running the Core Web Vitals checker, note the scope and the device that fails, then take the weakest metric into a lab audit to find its cause. Fix LCP at the largest element and the server response, INP in main-thread work, and CLS by reserving space. Field data needs time to reflect a fix.
Related tools
Which free tools pair with the Core Web Vitals checker?
Free tools that pair with the Core Web Vitals checker explain the field numbers. The PageSpeed Checker runs a Lighthouse lab audit with diagnostics for a failing metric. The Server Response Time Checker times the server phases behind a slow LCP. The Website Performance Test compares connection timing across probe locations in several regions.
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Questions
What do people ask about the Core Web Vitals checker?
People ask the Core Web Vitals checker FAQ what LCP, INP and CLS measure, what good values are, and what the 75th percentile means. They also ask why a page shows no data, how field data differs from lab data, how to improve LCP, and whether passing guarantees higher rankings, which it does not.
What does the Core Web Vitals Checker report?
It reports real-user LCP, INP and CLS at the 75th percentile from Chrome field data over the trailing 28 days and whether all available metrics are within the published good thresholds.
What are good Core Web Vitals values?
Google publishes a good, a needs-improvement and a poor threshold for each metric, assessed at the 75th percentile of real visits. This checker applies the published thresholds and shows each metric's verdict beside its value, so you read a pass or a fail instead of comparing numbers by hand.
What do LCP, INP and CLS actually measure?
LCP, Largest Contentful Paint, measures loading speed. INP, Interaction to Next Paint, measures responsiveness to input. CLS, Cumulative Layout Shift, measures visual stability. Together they reflect real perceived page experience for users.
Why does my page show no Core Web Vitals data?
Field data needs enough real Chrome traffic. Low-traffic pages fall back to origin-level data or report none at all. No data means insufficient samples, not that the page performs badly.
What is the 75th percentile in Core Web Vitals?
It means 75 percent of real page visits were at least this fast or stable. Google uses the 75th percentile so the assessment reflects most users, not just the fastest or an average, experience.
What is the difference between field data and lab data?
Field data is measured from real users' devices and networks over time, as this checker reports. Lab data comes from a single controlled test. Field data reflects genuine experience; lab data is reproducible but simulated.
How do I improve my Largest Contentful Paint?
Serve the main image or text quickly by optimizing and preloading the largest element, reducing server response time, trimming render-blocking resources, and using efficient caching so the largest element paints inside Google's good band.
Does passing Core Web Vitals guarantee higher rankings?
No. Search ranking uses many systems, and good Core Web Vitals do not guarantee a higher position. Treat the result as user-experience evidence, not a ranking promise.
Why is INP replacing older responsiveness metrics important?
INP measures the latency of real user interactions across the whole visit, not just the first. An INP inside Google's good band means the page reliably responds quickly whenever users tap or click.
Is this checker a lab speed test?
No. It reports real-user field data at the 75th percentile from Chrome over 28 days. For a controlled lab audit with reproducible opportunities, use a Lighthouse-based tool like the PageSpeed Checker instead.