Audit & Analysis

Core Web Vitals Checker — Measure LCP, CLS & INP

Measure Core Web Vitals — LCP, CLS and INP — plus TTFB, first paint, request count, page weight by resource type and your slowest requests, on any page you visit.

What is Performance Metrics?

The Performance Metrics in UltraDevKit helps you work with a live web page. Measure Core Web Vitals — LCP, CLS and INP — plus TTFB, first paint, request count, page weight by resource type and your slowest requests, on any page you visit.

Category

Audit & Analysis

Best for

Measure Core Web Vitals on a staging site that PageSpeed Insights cannot reach; Find which resource type is responsible for a heavy page

Runs on

Any page in Chrome

When you'd use it

• Measure Core Web Vitals on a staging site that PageSpeed Insights cannot reach
• Find which resource type is responsible for a heavy page
• Identify the slowest requests holding up a render
• Check whether a performance fix actually moved LCP

How to use Performance Metrics

1. Load the page normally, then open Performance Metrics.
2. Read LCP, CLS and INP against the good / needs-improvement thresholds.
3. Review page weight broken down by scripts, images, CSS and fonts.
4. Check the slowest requests list for the obvious offender.

Performance Metrics FAQ

How is this different from PageSpeed Insights?

PageSpeed needs a public URL and runs a synthetic test on Google's hardware. This measures the page as it actually loaded in your browser, which means it works on localhost, staging and pages behind a login.

Why is INP sometimes blank?

INP measures real interactions. If you have not clicked or typed on the page yet, there is nothing to report — interact first, then re-read.

Do these numbers match what Google uses for ranking?

Google ranks on field data from real Chrome users over 28 days. Your local reading is one sample on your own connection and device, which is ideal for debugging but not a substitute for Search Console.

Works well with