Free Technical SEO Tool

Core Web Vitals Checker for LCP, INP & CLS

Check whether a page passes Core Web Vitals for the selected device. Analyse LCP, INP and CLS for a single public URL using field data where available, with lab fallback shown clearly when real-user data is limited.

LCP • INP • CLS

Metrics checked

Mobile + Desktop

Device modes

Field + Lab

Source labels

Core Web Vitals Checker

Check LCP, INP, and CLS for a single URL using field data when available.

Check settings

Data handling

Field data is preferred. Lab data is used only when field data is limited or unavailable.

Free public checks are limited to 3 uses/day. CAPTCHA may appear for protection.Remaining today: 3

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What it checks

Focused checks for Core Web Vitals quality.

This page keeps the public workflow focused on the signals that determine whether a page passes Core Web Vitals for the selected device.

Use it during internal linking audits, content optimisation, technical SEO reviews, website migrations and content hub planning.

Vitals focus

Check the three CWV metrics

Focus on Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift instead of a broad PageSpeed score.

Data confidence

Label field, origin and lab sources

See whether the assessment uses page field data, origin field fallback, mixed sources, lab fallback or unavailable data.

Device control

Analyse Mobile or Desktop

Run a focused check for the selected device, with Mobile as the recommended default for public CWV checks.

Action path

Prioritise rule-based fixes

Identify whether loading, responsiveness or visual stability should be handled first with practical fix categories.

Why Core Web Vitals matter

A fast-looking page can still fail real users.

Core Web Vitals help teams understand whether a page loads slowly, responds late to interactions or shifts unexpectedly during loading. Wranker keeps the data source visible so teams know how much confidence to place in the check.

Find the weakest metric first

Prioritise Poor metrics before Needs Improvement metrics so performance work starts where it matters most.

Avoid false pass signals

Field data is preferred for pass/fail judgement, while lab diagnostics are clearly framed as debugging support.

Support SEO QA handoff

Use concise metric labels, source context and fix priorities for technical SEO QA and developer conversations.

How it works

From page URL to focused CWV workflow.

The landing page stays focused on the pre-submit workflow. The detailed output opens after the check runs.

01

Enter a page URL

Add a live public URL. The public checker is not intended for localhost, private IPs or internal URLs.

02

Select Mobile or Desktop

Choose the device you want to test. Mobile is the recommended default; Desktop is useful for comparison.

03

Run the CWV check

Wranker prepares a field-first assessment and uses lab fallback only when real-user data is limited.

04

Review the dashboard output

After submission, review CWV status, metric quality, source labels and rule-based fix priorities.

Who should use it

Built for focused performance SEO decisions.

Use the checker when you need a quick, clear signal before deeper diagnostics, developer handoff or project-level tracking.

Technical SEO specialists

Check which Core Web Vitals metric needs attention before opening deeper PageSpeed or technical audit workflows.

Developers

Confirm whether performance fixes are aimed at loading, interaction responsiveness or layout stability.

SEO agencies

Add focused CWV checks to audit, QA, reporting and client handoff workflows without running a full audit first.

Marketing and launch teams

Review campaign pages, service pages and launch pages before promoting traffic to slower or unstable experiences.

FAQs

FAQs about the Core Web . Vitals Checker

Clear answers about thresholds, data sources, devices and exports before you run the tool.

A Core Web Vitals Checker is a tool that checks whether a page passes the main Core Web Vitals metrics: LCP, INP and CLS.

The tool checks Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift.

A good LCP is 2.5 seconds or less. LCP above 2.5 seconds needs improvement, and above 4.0 seconds is poor.

A good INP is 200 milliseconds or less. INP above 200 milliseconds needs improvement, and above 500 milliseconds is poor.

A good CLS is 0.1 or less. CLS above 0.1 needs improvement, and above 0.25 is poor.

The tool should prefer field data where available. If page-level field data is unavailable, it may show origin-level field data or lab fallback with a clear label.

Lab data is useful for diagnostics, but it should not be treated as a full real-user Core Web Vitals pass. Field data is preferred for pass/fail assessment.

INP requires real-user interaction data. It may be unavailable when the page or origin does not have enough field data.

Mobile is the recommended default because mobile Core Web Vitals issues are often more visible. Desktop checks are useful for comparison.

Yes. Public exports may include CSV, PDF and JSON. You can also copy the summary, metrics and fix list where available.

Build better performance SEO workflows

Start with a focused Core Web Vitals check.

Use Wranker to check LCP, INP and CLS, compare Mobile and Desktop, prioritise fixes, export SEO reports and connect checks with deeper technical SEO workflows.

Core Web Vitals Checker & Page Speed Test | WRanker