What Are Core Web Vitals?

You've probably heard "Core Web Vitals" thrown around in SEO conversations. But what does it actually mean, and why should you care? Let's break it down in plain English.

What Are Core Web Vitals?

Core Web Vitals are three specific metrics Google uses to measure how good your website feels to use:

That's it. Three numbers that tell Google: "Is this website annoying to use?"

Why Do Core Web Vitals Matter for SEO?

Since 2021, Google has used these metrics as a ranking factor.

It's not the biggest ranking factor (content quality still matters most), but it's an easy win most sites ignore.

LCP

Largest Contentful Paint

How long until the main content appears on screen

Good Under 2.5s

Needs Work 2.5–4s

Poor Over 4s

What slows it down

• Large images that aren't compressed
• Slow server response time
• Heavy JavaScript blocking the page

Quick fixes

• Compress your images (use WebP format)
• Use a CDN (Cloudflare is free)
• Remove unused plugins/scripts

INP

Interaction to Next Paint

How quickly the page responds when you click, tap, or type

Note

INP replaced FID (First Input Delay) in March 2024.

Good Under 200ms

Needs Work 200–500ms

Poor Over 500ms

What causes bad INP

• Heavy JavaScript running in the background
• Too many third-party scripts (chat widgets, analytics, ads)
• Complex animations

Quick fixes

• Audit your plugins—remove what you don't need
• Defer non-essential JavaScript
• Avoid layout-triggering animations

CLS

Cumulative Layout Shift

How much the page layout moves around while loading

You know that feeling when you're about to click a button, and suddenly an ad loads and pushes everything down? That's layout shift.

Good Under 0.1

Needs Work 0.1–0.25

Poor Over 0.25

What causes bad CLS

• Images without width/height attributes
• Ads or embeds that load late
• Fonts that "flash" when loading

Quick fixes

• Always set width and height on images
• Reserve space for ads/embeds
• Use font-display: swap for custom fonts

How to Check Your Core Web Vitals

There are several free tools:

Quick Wins to Improve Core Web Vitals

If your scores are bad, start here:

Do Core Web Vitals Really Affect Rankings?

Yes, but let's be realistic:

Think of it this way: Great content on a slow, glitchy site will still struggle. Average content on a fast site won't magically rank #1.

But if your competitors have similar content and better Core Web Vitals? They win.

The Bottom Line

Core Web Vitals aren't complicated:

Fix these, and you've handled something most websites ignore.

Your Next Step

1

Check your Core Web Vitals score right now

2

Identify your worst metric

3

Apply one fix from this guide

4

Re-test in a week