What Is a Good Lighthouse Performance Score?

The Lighthouse Performance score runs from 0 to 100. But what score is “good”? And how much should you care about hitting a specific number vs. improving the underlying metrics?

Google’s Score Thresholds

Score	Category
90–100	Good (green)
50–89	Needs improvement (orange)
0–49	Poor (red)

Google designed these thresholds to reflect typical real-world performance distributions. A score of 90+ puts you in roughly the top 10–20% of sites on the web.

What the Score Is Based On

The Performance score is a weighted average of five metrics:

Metric	Weight
Total Blocking Time (TBT)	30%
Largest Contentful Paint (LCP)	25%
Cumulative Layout Shift (CLS)	25%
First Contentful Paint (FCP)	10%
Speed Index	10%

TBT + LCP = 55% of the score. If you can improve these two metrics, you’ll have the most impact on the number. For a full breakdown of each category, see What Is a Lighthouse Score?.

What Score Should You Target?

For most websites: 70+ on mobile is a reasonable baseline to aim for.

If you care about Core Web Vitals as an SEO factor: The score is less important than passing the individual Core Web Vitals thresholds (LCP < 2.5s, CLS < 0.1, INP < 200ms) in Google’s field data.

If you want to be competitive: 80+ on mobile puts you ahead of most sites in your category.

If you’re already at 80+: Returns diminish. The last 10 points often require significant effort for small real-world impact. Focus on field data at this point.

The Score vs. The Metrics: Which Matters More?

The score is a summary — it’s useful for quickly comparing pages or tracking trends. But the underlying metrics are what actually affect user experience and Google rankings.

A site with a 75 Lighthouse score and passing Core Web Vitals in field data is in better shape than a site with an 85 score and failing field data.

Focus on field data first. Check your Core Web Vitals in Google Search Console or PageSpeed Insights. Those numbers represent real users on real devices. Pass those thresholds before optimizing for lab score.

Why Different Tools Show Different Scores

Running the same URL through Chrome DevTools Lighthouse, PageSpeed Insights, and debugutils.dev may produce different scores. This is normal — the testing environment differs (we explain why in detail in PageSpeed Insights vs. Lighthouse):

• Your local Lighthouse uses your machine’s CPU and network
• PageSpeed Insights uses Google’s infrastructure
• debugutils.dev uses dedicated servers with controlled conditions

Scores can vary 5–15 points between environments. Run multiple tests on the same tool and average the results for a more reliable baseline.

Score Volatility

Lighthouse scores aren’t perfectly stable. The same page, run twice in a row, can produce scores that differ by 5–10 points. This is due to CPU throttling imprecision, background processes, and other environmental factors.

This means:

• Don’t celebrate a 2-point improvement — it may be noise
• A 10+ point change is probably real
• Run 3 tests and take the median for reliable comparisons
• Focus on metric trends, not single run scores

Honest Assessment by Score Range

90–100: Your site is genuinely fast. Check that Core Web Vitals field data also looks good. Don’t spend more time on performance optimization unless field data is failing.

75–89: Good shape, room to improve. Find the one or two biggest opportunities in your Lighthouse report and address them.

50–74: Meaningful performance issues. Images are probably unoptimized, caching may be missing, or JavaScript is heavy. Systematic optimization will pay off.

Under 50: Serious issues. Start with caching, then images, then JavaScript. A focused 2–4 hour optimization session should make a significant difference.

Run your URL on debugutils.dev to get your current score plus the specific opportunities with estimated time savings. To make sense of the full report, see our guide on how to interpret a Lighthouse report.