Free Core Web Vitals Checker
Enter a URL to measure your Core Web Vitals scores - LCP, CLS, and INP - using Google's PageSpeed Insights API.
What this Core Web Vitals checker measures
This free Core Web Vitals checker runs the page you enter through Google's PageSpeed Insights API and reports the three metrics Google uses as a ranking signal: Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and Interaction to Next Paint (INP). Each comes back with its measured value and a pass, needs-improvement, or fail rating against Google's thresholds.
These are the same measurements Google records in the Chrome User Experience Report, so they reflect what real visitors experience, not a synthetic lab-only score.
What each metric means
Understanding the three vitals tells you where to focus:
- LCP (loading): how long until the largest element in view has rendered. Good is under 2.5 seconds. See the LCP guide.
- CLS (visual stability): how much the layout shifts unexpectedly as the page loads. Good is under 0.1. See the CLS guide.
- INP (responsiveness): how quickly the page reacts to taps, clicks, and key presses. Good is under 200 milliseconds. See the INP guide.
How to improve your Core Web Vitals
LCP usually improves by compressing and correctly sizing the hero image, serving modern formats like WebP, preloading the main image or font, and cutting render-blocking scripts. CLS improves by setting explicit width and height on images and reserving space for anything that loads late, such as ads or embeds. INP improves by breaking up long JavaScript tasks and trimming third-party scripts that block the main thread.
A full AuditZap audit ties each vital to AI fix instructions for your stack, so you know which image, script, or setting to change rather than guessing.
Honest limits
This tool measures one URL at a time using field and lab data from the PageSpeed API. When a page has too little real-world traffic, Google may return lab-only estimates, which can differ from what your visitors see. To measure your key pages together and track them over time, run a full free audit.
Frequently asked questions
Is this Core Web Vitals checker free?
Yes, free and no signup, up to 15 checks per hour.
What are good Core Web Vitals scores?
LCP under 2.5 seconds, CLS under 0.1, and INP under 200 milliseconds are the "good" thresholds Google uses.
Do Core Web Vitals affect SEO?
Yes. They are part of Google's page experience signals, so poor vitals can hold back rankings, especially on mobile where the competition is close.
Why is my score different from another tool?
Scores vary with network, device, and whether the data is real-world field data or a lab estimate. This tool uses Google's PageSpeed API for consistency with Search Console.
Can I track vitals over time?
This tool is a one-off check. To monitor your pages with re-audits, run a full free audit.