If you have ever wondered how "good" your website really is, Google has a free tool that gives you a definitive answer. It is called Lighthouse, and it scores your website across four key areas: Performance, Accessibility, Best Practices, and SEO.
These scores are not vanity metrics. They directly affect how your site ranks on Google, how users experience it, and ultimately, whether visitors become customers. A website that scores 40 on performance and a website that scores 95 deliver fundamentally different user experiences, and Google knows the difference.
What is Google Lighthouse?
Lighthouse is an open-source tool built by Google that audits web pages against modern web standards. You can run it in several ways:
- Chrome DevTools: Right-click any page, select Inspect, go to the Lighthouse tab, and click "Analyze page load"
- PageSpeed Insights: Visit pagespeed.web.dev, enter any URL, and get a full report
- Command line: For developers, Lighthouse can be run via npm for automated testing
- Chrome extension: Install the Lighthouse extension for one-click audits
It simulates how a real user would experience your page on a mid-range mobile device on a 4G connection (the default throttling) and generates scores from 0 to 100 in four categories. This conservative simulation ensures that if your site performs well in the test, it will perform well for most real users.
The four categories explained
Performance (0-100)
This measures how fast your page loads and becomes interactive. It is weighted by five key metrics that together reflect the real-world loading experience:
Largest Contentful Paint (LCP): 25% of score
What it measures: How quickly the main content of the page loads. This is typically the hero image, a large heading, or a video thumbnail.
Target: Under 2.5 seconds (good), 2.5-4.0 seconds (needs improvement), over 4.0 seconds (poor)
Why it matters: LCP is Google's primary metric for perceived load speed. If your main content takes 5 seconds to appear, visitors see a blank or partially loaded page for 5 seconds, and most will leave.
Total Blocking Time (TBT): 30% of score
What it measures: How long the page is unresponsive to user input during loading. This happens when JavaScript is executing and blocks the main thread.
Target: Under 200ms (good), 200-600ms (needs improvement), over 600ms (poor)
Why it matters: If a user tries to tap a button or scroll while the page is still loading heavy JavaScript, nothing happens. This feels broken.
Cumulative Layout Shift (CLS): 25% of score
What it measures: How much the page layout shifts while loading. Those annoying jumps where you are about to tap something and it moves because an image or ad loaded above it.
Target: Under 0.1 (good), 0.1-0.25 (needs improvement), over 0.25 (poor)
Why it matters: Layout shifts are one of the most frustrating user experiences on the web. They cause misclicks, disorientation, and a feeling that the site is unreliable.
First Contentful Paint (FCP): 10% of score
What it measures: How quickly the first piece of content appears on screen: any text, image, or SVG.
Target: Under 1.8 seconds
Speed Index: 10% of score
What it measures: How quickly content is visually displayed during loading, measuring the visual progression from blank to complete.
Target: Under 3.4 seconds
Accessibility (0-100)
This measures how usable your site is for people with disabilities. It checks for automated accessibility violations including:
- Proper heading hierarchy (H1, H2, H3 in order, no skipped levels)
- Alt text on all meaningful images
- Sufficient color contrast between text and background
- Keyboard navigability for all interactive elements
- ARIA labels on non-standard interactive elements
- Form labels properly associated with inputs
- Properly defined page language
- Visible focus indicators
What it means for your business: Beyond being the right thing to do, accessibility issues can expose your business to legal risk. India's Rights of Persons with Disabilities Act (2016) and the international landscape of accessibility lawsuits are expanding. Accessible sites also tend to be more usable for everyone. Read our complete accessibility guide for detailed implementation advice.
Best Practices (0-100)
This checks for modern web development standards:
- HTTPS usage (SSL certificate)
- No browser console errors
- Proper image aspect ratios (no stretched or squished images)
- No deprecated APIs or outdated JavaScript features
- Safe cross-origin links (rel="noopener" on external links)
- Proper Content Security Policy headers
- No third-party cookies issues
What it means for your business: Best practices violations often indicate security issues or outdated code that could break in future browser updates.
SEO (0-100)
This checks basic SEO requirements:
- Presence of title tag and meta description
- Crawlable links (not blocked by robots.txt or noindex)
- Valid robots.txt file
- Readable font sizes on mobile (no text smaller than 12px)
- Tap targets properly sized (minimum 48x48px)
- Page has a valid hreflang (for multilingual sites)
- Document has a meta viewport tag
What it means for your business: A low SEO score means Google may not index your site properly, reducing your visibility in search results. For a deeper guide, read our SEO basics for small businesses.
What is a good Lighthouse score?
Google uses this colour coding:
- 0-49 (Red): Poor. Significant issues need fixing.
- 50-89 (Orange): Needs improvement. Functional but not optimized.
- 90-100 (Green): Good. Meets modern web standards.
For a small business website, aim for:
- Performance: 90+
- Accessibility: 90+
- Best Practices: 90+
- SEO: 90+
A perfect 100 across all categories is achievable for static websites with clean code and optimized images.
Real score comparisons
To put these numbers in context, here is how different types of websites typically score on Performance:
- Average WordPress site (with plugins): 35-55
- Wix/Squarespace template site: 40-65
- Custom-built React SPA: 50-75 (depending on optimization)
- Well-optimized static site: 90-100
- Web Waala generated site: 90-100
The difference between a score of 45 and 95 is not subtle. It is the difference between a page that loads in 1.5 seconds and one that takes 6+ seconds. It is the difference between a visitor who stays and one who hits the back button.
Why most websites score poorly
The majority of websites score below 70 on performance. Common reasons:
- Heavy images. Unoptimized images are the number one performance killer. A single 5MB hero image can tank your score. Many business owners upload photos directly from their camera without any optimization.
- Too much JavaScript. WordPress sites with 20 plugins, each loading its own JavaScript bundle, are notoriously slow. Many template builders inject hundreds of kilobytes of JavaScript even for simple pages.
- No caching. Without proper cache headers, browsers re-download everything on every visit.
- Render-blocking resources. CSS and JavaScript files that block the page from rendering until they are fully loaded.
- Third-party scripts. Analytics, chat widgets, ad scripts, and social media embeds all add weight. Each third-party script makes an external network request, adding latency.
- Unoptimized web fonts. Loading 5 font weights when you only use 2, or not using font-display: swap.
- No lazy loading. Loading all images upfront, including those far below the fold that the user may never scroll to.
Step-by-step audit walkthrough
Here is how to audit your own website using Lighthouse:
Step 1: Run the audit
Open your website in Chrome. Press F12 (or right-click and select "Inspect"). Click the "Lighthouse" tab. Select "Mobile" (this is what Google uses for ranking). Check all categories. Click "Analyze page load."
Step 2: Read the scores
Look at each of the four category scores. Anything below 90 (orange or red) needs attention. Focus on the lowest-scoring category first.
Step 3: Review the opportunities
Lighthouse lists specific opportunities for improvement, sorted by estimated impact. Each opportunity tells you what to fix and how much time it could save. Start with the highest-impact items.
Step 4: Check the diagnostics
Below opportunities, the diagnostics section provides detailed technical information about potential issues. These are more informational but can reveal important problems.
Step 5: Fix and re-test
Make the recommended changes, deploy them, and run Lighthouse again. Scores should improve. Repeat until you reach your target scores.
Common fixes with before and after impact
Compress and resize images
Before: Hero image is 3.2 MB JPEG, 4000x3000px
After: Hero image is 85 KB WebP, 1200x800px
Impact: Performance score jumps from 55 to 78 from this single change
Remove unused JavaScript
Before: Page loads 1.5 MB of JavaScript (jQuery, Bootstrap JS, 8 plugins)
After: Page loads 150 KB of JavaScript (only what is actually used)
Impact: TBT drops from 1200ms to 180ms, performance score jumps from 45 to 82
Add image dimensions
Before: Images load without width/height attributes, causing layout shifts
After: All images have explicit width and height, eliminating CLS
Impact: CLS drops from 0.35 to 0.02, performance score improves by 10-15 points
Implement lazy loading
Before: All 15 images on the page load immediately
After: Only the first 3 images load initially; the rest load as the user scrolls
Impact: Initial page weight drops by 60%, LCP improves significantly
Use font-display: swap
Before: Custom fonts block rendering for 1-3 seconds (invisible text)
After: System font shows immediately, custom font swaps in when ready
Impact: FCP improves by 1-2 seconds, no more invisible text
How Web Waala sites score
Every website generated by Web Waala is built to achieve a 90+ Lighthouse score across all four categories. We accomplish this with:
- Clean, semantic HTML5 (no bloated framework output)
- Pre-optimized images from Unsplash with proper sizing and lazy loading
- Minimal, purpose-built CSS with no unused styles
- SEO meta tags and schema markup generated automatically
- Proper heading hierarchy and accessibility attributes
- Responsive design that works across all devices
- Font optimization with preconnect and font-display: swap
You do not need to understand Lighthouse to benefit from it. When your website is built right from the start, the scores take care of themselves.
Learn more about why static websites outperform dynamic ones and our approach to built-in SEO. Get started with Web Waala for free.
