Core Web Vitals Checker

The three Core Web Vitals

Google's Core Web Vitals are three metrics designed to capture real user experience:

LCP — Largest Contentful Paint

LCP measures how long it takes for the largest element above the fold (usually a hero image, headline, or video) to render. It tells you how quickly your page feels loaded to a visitor.

CLS — Cumulative Layout Shift

CLS measures visual stability. Every time content on your page jumps around as it loads (because an ad loaded, or a font swapped in, or an image had no dimensions), your CLS score goes up.

INP — Interaction to Next Paint

INP replaced FID in March 2024 as a Core Web Vital. It measures the latency between a user interaction (click, tap, key press) and the next visual update.

How to check yours

Paste your URL into the form at the bottom. We'll run a Lighthouse audit on both mobile and desktop and grade each Core Web Vital using Google's exact thresholds. Green means good, amber means needs improvement, red means fix this.

How to fix poor Core Web Vitals

To improve LCP:

• Compress and properly size your hero image
• Use <link rel="preload"> on your largest above-the-fold asset
• Move to a faster host or add a CDN
• Inline critical CSS instead of blocking on an external stylesheet

To improve CLS:

• Always set width and height attributes on <img> and <video> elements
• Reserve space for ads and embeds before they load
• Use font-display: optional or preload your custom fonts

To improve INP:

• Break up long JavaScript tasks (anything over 50ms)
• Defer non-essential third-party scripts
• Use requestIdleCallback for non-critical work
• Avoid heavy work in event handlers — let the browser paint first