What is a good CLS score?

Google considers a CLS score of 0.1 or less "Good." Scores between 0.1 and 0.25 "Need Improvement," and scores above 0.25 are "Poor." Aim for 0.1 or below to pass Core Web Vitals.

Where do I find my CLS score?

Run a Lighthouse audit in Chrome DevTools (Performance tab), use PageSpeed Insights at pagespeed.web.dev, or check Google Search Console under "Core Web Vitals" for field data from real users.

What causes a high CLS score?

The most common causes are images without explicit width/height attributes, dynamically injected banners or ads, web fonts that cause a flash of unstyled text (FOUT), and content inserted by third-party scripts before the page is fully loaded.

Does CLS affect Google rankings?

Yes. CLS is one of the three Core Web Vitals signals used in Google's page experience ranking factor. Poor CLS can negatively affect organic search rankings, especially in competitive SERPs.

How is CLS calculated?

CLS is the sum of all individual layout shift scores that occur without a 500 ms gap of user input. Each shift score = impact fraction × distance fraction. The metric captures the worst burst window (largest session window) over the page lifetime.

CLS Score Interpreter

Enter your CLS score to get an instant grade, plain-English explanation, and fix recommendations for your Core Web Vitals.

Your CLS Score

Enter the score shown in Lighthouse or PageSpeed Insights.

CLS Score

Enter a CLS score on the left to see your grade and fixes.

Summary

Cumulative Layout Shift (CLS) measures how much page content unexpectedly moves during load. A score below 0.1 is "Good," 0.1–0.25 is "Needs Improvement," and above 0.25 is "Poor" by Google's Core Web Vitals thresholds. This tool grades your score, explains what likely causes it, and gives you a prioritized checklist of developer fixes to bring it into the green.

How it works

Enter your CLS score from Lighthouse, PageSpeed Insights, or Chrome DevTools.
The tool grades your score against Google's Good / Needs Improvement / Poor thresholds.
See the most common root causes ranked by typical impact.
Work through the fix checklist to eliminate layout shifts one by one.
Re-run a Lighthouse audit after each fix to track progress.

Use cases

Diagnose a failing Core Web Vitals score before a site launch.
Prioritize layout-shift fixes during a performance sprint.
Explain CLS impact to a non-technical stakeholder.
Validate which fix categories apply to your current score range.
Use as a reference during code review for image and font loading.
Educate junior developers on the causes and remedies of layout shift.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu

CLS Score Interpreter

Your CLS Score

What This Means

Likely Causes

Fix Checklist

Next Step

Summary

How it works

Use cases

Frequently Asked Questions

CLS Score Interpreter

Use the CLS Score Interpreter

Your CLS Score

What This Means

Likely Causes

Fix Checklist

Next Step

Summary

How it works

Use cases

Frequently Asked Questions