What are Core Web Vitals?

Google's three user-experience metrics: LCP measures how fast the largest visible element loads, INP measures how quickly the page responds to interactions, and CLS measures how much the layout shifts unexpectedly while loading.

Can this check any website's vitals?

No. The checker measures the page it is running on, using the browser's PerformanceObserver API. To test a site, navigate to that site in your browser and run the tool there.

What scores count as good?

Google's thresholds: LCP under 2.5s, INP under 200ms, and CLS under 0.1 are rated good. The tool applies these official thresholds automatically.

How is this different from PageSpeed Insights?

PageSpeed Insights runs a simulated lab test plus aggregated field data from real users. This checker measures live in your own browser on your device and connection, which is faster and reflects your real experience.

Do I need to install anything?

No. It uses built-in browser APIs, so it works instantly in any modern browser with no extension or signup.

How do I improve a poor LCP score?

Compress and preload your hero image, serve assets from a CDN, and remove render-blocking scripts and stylesheets above the fold. The tool shows a targeted tip for whichever metric scores poorly.

Web Vitals Checker - Free Core Web Vitals Tester | IconVault

Measure Core Web Vitals LCP, INP and CLS of the page you are on with real browser metrics. Free, instant, no signup.

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Web Vitals Checker

Measure real LCP, INP and CLS in your browser

5 of 5 free uses left

This measures this page, in your browser, from the moment you press Measure. It cannot test arbitrary URLs. LCP and CLS capture everything since page load (buffered), while INP needs real interactions: click around after starting.

Core Web Vitals

Google's thresholds: green is good, amber needs improvement, red is poor

LCP

Largest Contentful Paint

Measuring…

Speed up the largest visible element: compress the hero image, preload it, serve it from a CDN, and avoid render-blocking scripts above the fold.

INP

Interaction to Next Paint

Measuring…

Reduce input delay: split long JavaScript tasks, defer non-critical scripts, and keep event handlers light so clicks respond fast.

CLS

Cumulative Layout Shift

Measuring…

Stop layout jumps: always set width and height on images and embeds, reserve space for ads and dynamic banners, and avoid inserting content above existing content.

How to read this

LCP under 2.5s is good. It is the moment the biggest visible element finished loading.
INP under 200ms is good. It is the worst click-to-response delay seen. No interactions yet means no INP score.
CLS under 0.1 is good. It adds up every unexpected layout jump on the page.

Field vs lab

This is a lab measurement on your device and connection. Google's official scores come from real users over 28 days (the CrUX dataset), so treat this as a diagnostic snapshot, not your search ranking score.

5 of 5 free measurements left.

About this tool

IconVault's Web Vitals Checker measures the Core Web Vitals of the page you are currently viewing, using the browser's own PerformanceObserver API. It captures LCP (Largest Contentful Paint), INP (Interaction to Next Paint) and CLS (Cumulative Layout Shift), rates each against Google's official thresholds, and gives a plain-English tip for improving any metric that needs work.

Because it reads real browser performance entries, the numbers reflect genuine rendering behavior rather than estimates. It is free with no signup and runs entirely in your browser. The honest limit: it measures the page you are on, not arbitrary URLs, so to test a site, open that site and run the checker there. Like all field-style metrics, results vary with your device and connection, so treat them as guidance alongside lab tools like PageSpeed Insights.

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Web Vitals Checker - Free Core Web Vitals Tester | IconVault

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