The 2026 SEO Audit Checklist: The Checks We Run on Every Site

TL;DR: Our audit scores a site in seven categories and weights them: technical SEO 22%, content quality 23%, on-page SEO 20%, structured data 10%, performance 10%, AI search readiness 10% and images 5%. The overall score is the weighted average, from 0 to 100. Below is every check we run in each category and what counts as a pass. Anything that stops a page being indexed is critical regardless of category. Test a single page right now with the free Website health check, or get the whole site checked with the full report.

Most SEO audit checklists online are either 12 items long and useless, or 250 items long and also useless, because nobody can tell which of the 250 matter. This one is the list we actually run, in the order we run it, with the weights we use to turn it into a score.

What does an SEO audit check in 2026?

An SEO audit checks whether search engines and AI assistants can find a site's pages, understand them and trust them enough to show them. In 2026 that means seven areas: technical health (crawling, indexing, HTTPS, redirects), content quality (depth, accuracy, who wrote it), on-page elements (titles, descriptions, headings, internal links), structured data, performance measured as Core Web Vitals, readiness for AI search (crawler access, server-rendered text, quotable answers), and images. The AI search category is the one that changed most in the last two years, but it did not replace anything. Google states that its AI features run on the same systems as regular Search, so a site with weak technical and content foundations does badly in both. A good audit ends with a prioritised list, because a flat list of 80 findings with no order is how audits end up in a drawer.

How are the categories weighted?

The overall score is the weighted average. Take the made-up dental clinic from our worked example, with illustrative scores of technical 84, content 80, on-page 86, structured data 74, performance 88, AI readiness 78 and images 80. Multiply each by its weight and add them up and you get 82.08, reported as 82. The weakest category, structured data at 74, pulls the total down by about one point, because it carries only 10% of the weight. A content score ten points lower would cost more than twice that.

Technical SEO checks (22%)

These decide whether the rest of the audit matters. A beautiful page that is not indexed scores zero in practice.

• robots.txt returns 200, lives at the root, and does not disallow pages you want in search. Google's robots.txt introduction is the reference.
• No accidental noindex. Check the <meta name="robots"> tag and the X-Robots-Tag header on key pages. Staging settings shipped to production are the classic case.
• XML sitemap lists every indexable page and nothing else (no redirects, no 404s, no noindexed URLs), and is submitted in Search Console.
• Canonical tags point each page at itself, or at the real original when there are duplicates, following Google's canonicalization guidance.
• HTTPS everywhere, with HTTP and www/non-www variants redirecting in a single 301 hop.
• No redirect chains longer than one hop on internal links, and no internal links to 404s.
• Mobile parity. Google indexes the mobile version, so the mobile page must carry the same content, headings and structured data as desktop.
• Main content present in the raw HTML the server sends, so a crawler that skips JavaScript still reads it.
• hreflang for multilingual sites: every language version lists all versions including itself, plus x-default.
• Security headers: at least HSTS and X-Content-Type-Options, ideally a Content Security Policy.

Content quality checks (23%)

Content carries the most weight because it is the part that decides whether a page deserves to rank once it can. We use Google's helpful content guidance and its Who, How and Why questions as the frame.

• Each important page answers its query fully. Word count is not a ranking factor, but a 150-word service page rarely answers anything.
• Visible authorship on advice content: a byline that links to a page explaining who the author is.
• First-hand evidence: photos of your own work, real numbers, case studies, prices. This is the part competitors and AI-written pages cannot copy.
• Accurate and dated. Claims are sourced; pages that give advice show when they were last reviewed.
• No thin or duplicate pages competing with each other for the same query.
• Trust pages exist: about, contact with a real address or phone, privacy policy.

On-page SEO checks (20%)

• Unique title per page, leading with the topic. Google shortens titles by pixel width, so roughly 50 to 60 characters is a safe target. Google explains how it picks title links.
• Unique meta description of about 120 to 160 characters that a person would want to click.
• Exactly one H1 that names the page's topic, and headings in order (no H2 jumping to H4).
• Descriptive internal links: every page is linked from at least one other page, with anchor text that says where it goes.
• Clean URLs: readable, lowercase, hyphenated, stable.
• Open Graph tags so shared links show the right title and image.

Structured data checks (10%)

• JSON-LD format, which Google recommends over microdata.
• Organization or LocalBusiness on the home page, Article with author on posts, Product or Service where relevant, BreadcrumbList on deeper pages.
• Validates in the Rich Results Test and the Schema.org validator.
• Matches the visible page. Marked-up reviews, prices and FAQs must appear on the page itself.
• No retired types. Google stopped showing HowTo rich results in 2023 and restricted FAQ rich results to a small set of sites, as announced in its 2023 update. FAQ markup can still describe a real FAQ; just do not expect stars or dropdowns in results.

Performance checks (10%)

We use Google's Core Web Vitals thresholds, measured at the 75th percentile of real visits:

• Field data first. If the Chrome UX Report has data for your site, that is what counts. Lab scores are for diagnosis.
• Mobile passes, because mobile is where most sites fail.
• Page weight is reasonable: compressed images, no autoplaying video or embeds loading on first view.

The full walkthrough is in Core Web Vitals in 2026.

AI search readiness checks (10%)

• AI search crawlers allowed in robots.txt: OAI-SearchBot, ChatGPT-User, PerplexityBot, Claude-SearchBot and Bingbot, as well as Googlebot.
• No CDN or firewall rule silently blocking them.
• Answer-first passages under question-style headings.
• Facts in text, not in images or PDFs only.
• Entity signals: consistent business name, address and profiles across the site and its structured data.
• llms.txt present or not. We record it and give it no weight, for reasons explained in llms.txt and robots.txt for AI crawlers.

Image checks (5%)

• Alt text that describes the image on every meaningful image; empty alt="" on decorative ones.
• Width and height attributes on every <img> so the page does not jump while loading.
• Modern formats (WebP or AVIF) and sizes that match how large the image is displayed.
• Lazy loading below the fold, never on the main image at the top of the page.

What tools do you need to run the checklist yourself?

You can run nearly every check on this list with free tools, and most of them come from Google. Google Search Console shows which pages are indexed, which are excluded and why, and it is where you submit a sitemap. PageSpeed Insights gives you Core Web Vitals from real Chrome users when your site has enough traffic, and a Lighthouse lab test when it does not. The Rich Results Test validates structured data against what Google supports. Your browser's "view source" answers the JavaScript question in seconds. Bing Webmaster Tools matters more than people think, because Bing's index feeds Copilot. What free tools do less well is crawl a whole site and weigh hundreds of findings against each other, and that is the gap a paid audit should fill. Our free Website health check scores one page against the on-page and technical basics.

How do you prioritise what the audit finds?

We sort every finding into four severities, and severity beats category. A critical technical issue outranks every content issue, but a high-severity content gap outranks a low-severity technical one.

• Critical: blocks indexing or risks a penalty. Fix today.
• High: clearly holds back rankings or conversions. Fix this week.
• Medium: a real improvement. Fix this month.
• Low: polish. Backlog it.

A good audit also says how much effort each fix takes, because "add FAQ markup to a dozen existing answers" (a few hours for a developer) and "write an informational content section" (weeks) should never sit in the same column without comment.

You can run most of this list yourself with free tools; the free SEO + GEO guide walks through each check with the tool to use. If you want it run across every page, with the score and the fix list done for you, that is the full report.