Free SEO check: how to read your website score and what to improve first

You have run a free SEO check and you see two numbers: a performance score and an SEO score. But what do they actually mean? And which improvements should you tackle first? In this article I explain it.

What does Lighthouse measure?

Google Lighthouse is the technology behind tools like PageSpeed Insights. It analyses your website on four areas:

• Performance — how fast does your page load?
• SEO — does Google understand what is on your page?
• Accessibility — is your website usable for everyone?
• Best Practices — do you follow security and quality guidelines?

In a free SEO check we focus on the two most impactful scores: Performance and SEO.

What do the scores mean?

Lighthouse scores from 0 to 100. The colour coding gives a quick indication of how you are doing:

• 90–100 (green) — Excellent. Your website performs well. There is little action needed, but small optimisations can make the difference.
• 50–89 (orange) — Needs improvement. Your website works, but there are clear bottlenecks affecting your ranking and user experience.
• 0–49 (red) — Critical. Serious issues that require your immediate attention. A slow or poorly optimised site loses visitors and ranks lower in Google.

Performance: the most visible score

The performance score is about speed. A slow website costs you visitors — research shows that more than half of users abandon a page that takes longer than 3 seconds to load on mobile.

What contributes to a low performance score?

• Large images that are not compressed or in the wrong format (use WebP)
• Unused JavaScript or CSS that still gets loaded
• No caching — the browser has to download everything again each time
• Slow server response time — cheap hosting can be a bottleneck here

The three core metrics Lighthouse measures are LCP (Largest Contentful Paint), TBT (Total Blocking Time) and CLS (Cumulative Layout Shift). Together they form the Core Web Vitals — official ranking factors from Google.

SEO: more than just keywords

The SEO score from Lighthouse measures the technical SEO foundation of your page. It is not about keyword strategy, but about fundamental signals that Google uses to understand your site.

What does Lighthouse check for SEO?

• Meta title and meta description present and unique?
• Alt texts on images — does Google understand what is shown?
• Mobile-friendly — is the viewport correctly set?
• HTTPS — are you using a secure connection?
• No blocked resources — can Google fully read your page?

A score of 90+ on SEO means your technical foundation is in order. Lower scores point to missing metadata or configuration errors that confuse Google.

What can you improve yourself?

Some improvements can be made without technical knowledge:

1. Compress images — use tools like Squoosh or TinyPNG before uploading images
2. Fill in meta tags — make sure every page has a unique title (50–60 characters) and description (120–160 characters)
3. Add alt texts — briefly describe what is shown in each image
4. Activate HTTPS — ask your hosting provider for an SSL certificate (often free via Let’s Encrypt)

These four steps resolve a large part of the most common SEO errors.

When should you bring in an expert?

Some problems require technical knowledge:

• Your LCP is higher than 2.5 seconds on mobile — this requires server or code optimisation
• Your Core Web Vitals are in the red in Google Search Console
• You have technical SEO issues such as duplicate content, wrong canonicals or crawl errors
• Your site loads slower after every update — a sign of code bloat or plugin conflicts

In those cases, a thorough audit and targeted approach is far more effective than searching around yourself.

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Want to know how your website scores? Run the free SEO check and receive your Lighthouse scores instantly. Are the scores too low? Then get in touch via the website development page — I am happy to take a look with you.