--- title: "Lighthouse audits" description: "Run a Google Lighthouse audit on a page to score its performance, accessibility, best practices and SEO, read its Core Web Vitals and real-user data, and fix its issues." url: https://help.rankprompt.com/en/articles/62-lighthouse-audits collection: "Site health" updated: 2026-10-25 language: en --- # Lighthouse audits Run a Google Lighthouse audit on a page to score its performance, accessibility, best practices and SEO, read its Core Web Vitals and real-user data, and fix its issues. Lighthouse is Google's open source tool for auditing a web page. Site health runs it for you on the pages you track, on the device you picked for each page (mobile or desktop). ## Running an audit 1. Open **Site health** and pick the **Lighthouse** tab 2. Select a page (or click **Add** in the header to add one first) 3. Click **Run audit** (**Re-run audit** once it has one) An audit costs 1 credit and takes about a minute. Running audits needs Starter or higher; owners and editors can run them. * * * ## The four scores

Score

What it measures

Performance

Page load speed

Accessibility

Usability for all, screen readers and keyboards included

Best practices

Modern standards: HTTPS, no console errors, safe libraries

SEO

Search optimization: title, description, crawlable links, mobile friendliness

90 to 100 is good, 50 to 89 needs improvement, below 50 is poor. ## Core Web Vitals (lab) Measured in the simulated run:

Metric

Good

Largest Contentful Paint (main content visible)

2.5 s or less

First Contentful Paint (first content painted)

1.8 s or less

Total Blocking Time (delay before the page responds)

200 ms or less

Cumulative Layout Shift (how much the layout jumps)

0.1 or less

Time to First Byte (server response)

800 ms or less

## Real-user data (CrUX) Below the lab metrics, **Real-user data (CrUX)** shows how real Chrome users experienced the page over the last 28 days, at the 75th percentile. This is what Google uses for ranking. A page with little traffic shows the whole domain's figures instead, or no data yet. * * * ## Issues The issues list shows what to fix, with its impact (**High**, **Medium**, **Low**). Filter by impact, and open an issue for the details. After a new audit, each issue is marked **New**, **Worse**, **Still failing** or **Resolved now**, and the list says how many issues were fixed since the previous audit. Common fixes: - **Performance**: compress and resize images, defer scripts that are not needed right away, use a CDN - **Accessibility**: add alt text, raise color contrast, label form fields - **Best practices**: serve everything over HTTPS, fix JavaScript errors, update old libraries - **SEO**: write a meta description, keep titles about 50 to 60 characters, use normal links * * * ## Audit history **Audit history** lists earlier runs of the page with their scores. Open one to see it in full and **Back to latest** to return. Owners and editors can **Delete audit**. The score chart shows the trend across runs. Scores move a few points between runs because of network and server timing. Look at the trend, not one run. ## When an audit fails The page shows why and what to try. The usual causes: the page is not public, a firewall blocks audit tools, or it timed out. Check the page opens in a private window, then run it again. If Lighthouse cannot run, **Technical audit** checks what it can. * * * ## Next steps - [Technical SEO audit](https://help.rankprompt.com/en/articles/63-technical-seo-audit.md) - [Competitor SEO comparison](https://help.rankprompt.com/en/articles/64-competitor-seo-comparison.md) - [Site health overview](https://help.rankprompt.com/en/articles/61-site-health-overview.md) * * * ## Questions? Email [support@rankprompt.com](mailto:support@rankprompt.com) and I'll help.