Core Web Vitals

Last updated: April 2026

Core Web Vitals are three user-experience metrics Google uses as search ranking signals. They measure loading speed, interactivity, and visual stability. Poor scores can hurt search rankings.

The three metrics

LCP — Largest Contentful Paint measures how long it takes for the largest visible element (hero image, heading) to render. Target: under 2.5 seconds.

INP — Interaction to Next Paint measures how quickly the page responds to user interactions (clicks, taps, key presses). Replaced FID in March 2024. Target: under 200ms.

CLS — Cumulative Layout Shift measures how much the page layout shifts unexpectedly during loading. Target: under 0.1.

Thresholds

Metric   Good          Needs Improvement   Poor
LCP      < 2.5s        2.5s - 4.0s         > 4.0s
INP      < 200ms       200ms - 500ms       > 500ms
CLS      < 0.1         0.1 - 0.25          > 0.25

Common LCP fixes

<!-- Preload the LCP image -->
<link rel="preload" as="image" href="/hero.webp" fetchpriority="high">

# Nginx: add Cache-Control for images
location ~* \.(jpg|webp|png)$ {
    add_header Cache-Control "public, max-age=2592000" always;
}

Common CLS fixes

<!-- Always set width and height on images -->
<img src="hero.webp" width="1200" height="600" alt="Hero">

<!-- Reserve space for ads and embeds -->
<div style="min-height: 250px">[ad slot]</div>