What Is the Google Lighthouse Score and How Do You Improve It?
Did you know Google keeps a report card for your website? It is called Lighthouse, it scores from 0 to 100 and it evaluates aspects that directly affect your visitors' experience, and your ranking in search results.
Most small business sites score lower than they should. Competitors who optimise their scores appear higher on Google and convert more. This article explains what Lighthouse is, what it evaluates and how to improve it.
What Google Lighthouse Is
Lighthouse is a free Google tool built into Chrome. It runs an automatic audit of any web page and returns scores from 0 to 100 in four categories.
To check your site's score right now: open Chrome, go to your site, press F12 (or right-click and select "Inspect"), click the "Lighthouse" tab and then "Analyze page load".
You can also use the online version, PageSpeed Insights, without installing anything: go to pagespeed.web.dev, paste the URL and get the report in seconds.
The 4 Metrics Evaluated
1. Performance
Measures the loading speed as the user perceives it. The main metrics are Google's Core Web Vitals:
- LCP (Largest Contentful Paint): the time until the largest visible element has loaded. Target: under 2.5 seconds.
- INP (Interaction to Next Paint): how quickly the site responds to user interactions. Target: under 200ms.
- CLS (Cumulative Layout Shift): visual stability, meaning elements that "jump" while loading. Target: under 0.1.
2. Accessibility
Assesses whether the site can be used by everyone, including people with visual or motor impairments. It checks colour contrast, keyboard navigation, screen reader compatibility, ARIA attributes and form labels.
3. Best Practices
Confirms that the site follows modern development standards: it uses HTTPS, has no browser console errors, uses no deprecated APIs, images have the correct aspect ratio and JavaScript libraries are up to date.
4. SEO
Checks basic technical optimisation elements: meta title and description present, viewport configured, structured data (Schema.org), alt text on images, links with descriptive text and no blocking by robots.txt.
What Each Score Means
| Score | Rating | What to Do |
|---|---|---|
| 90 – 100 | Excellent (green) | Monitor and maintain |
| 50 – 89 | Needs improvement (orange) | Identify and fix the highest-impact items |
| 0 – 49 | Poor (red) | Urgent action: it is hurting ranking and conversion |
How to Improve the Score
The highest-impact improvements on most sites are:
- Compress images and use the WebP format: images are usually 60-70% of a page's weight. WebP is 30-80% lighter than JPEG at equivalent quality.
- Lazy loading: load images only when they are about to enter the screen, instead of all at once.
- Minify CSS and JavaScript: removing whitespace and comments reduces file size without changing functionality.
- Eliminate render-blocking resources: CSS and JS in the <head> that delay the page load.
- Configure server caching: static files stored in the visitor's browser reduce later loads.
- Use a CDN: serving files from servers close to the visitor reduces latency.
Why 90+ Makes a Real Difference to the Business
It is not just a technical matter. Google's numbers are clear:
- Sites that pass the Core Web Vitals are 24% less likely to have users abandon the page
- Each extra second of loading time reduces conversions by 7%
- Google has used the Core Web Vitals as a ranking factor since 2021, so slow sites appear lower
A site with a Lighthouse score of 95+ does not just load faster. It appears higher on Google and converts more visitors into customers.
My web development services include a Lighthouse audit as part of the process. Custom HTML/CSS/JS sites reach scores of 90 to 100 natively. If you want to know your site's current score and what can be improved, ask for a free review or get in touch through the form or WhatsApp.
Want to know how your website is doing?
Ask for a free review: within 48 hours you get an analysis of your website and of what shows up on Google for your service.
