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SEO checker tools: what a free audit really tells you, and the 30 minute sequence to run today

Which free tools cover which checks, why the score out of 100 is the least useful number on the report, and the order to fix things in once you have the list.

Published by AI Knows Us · Updated 12 October 2026

An SEO checker crawls your pages the way a search engine would and reports what is broken: pages blocked from indexing, wrong canonical tags, broken links and redirect chains, missing or duplicate titles and descriptions, thin pages, orphan pages, slow templates and invalid structured data. For a site under a few hundred URLs, free tools cover all of it. Google's own set, Search Console plus PageSpeed Insights plus the Rich Results Test, answers the questions that matter most, and a free desktop crawl fills in the structural picture. The one number to ignore is the score out of 100, because that is a weighting a vendor chose, not a measurement of anything Google does.

This page covers which tool answers which question and the order to act in. For presenting the findings to a client, that is a reporting job and a different document.

The checks that matter, in priority order

Any audit, free or paid, is answering this list. Work down it, because a problem near the top makes every problem below it irrelevant.

  • Can Google reach it? robots.txt rules, noindex tags, canonical tags pointing elsewhere, HTTP status codes, pages orphaned from every menu and link.
  • Is Google indexing the version you intended? One hostname, one protocol, no duplicate parameter URLs competing, sitemap contents matching what you want indexed.
  • Does the page say what it is about? A unique title, a written description, one H1, and the subject present in the first paragraph.
  • Is the content worth indexing? Thin pages, near duplicates, auto generated archive pages, templates with three sentences of unique text.
  • Do the internal links point at the right pages? Depth from the homepage, orphans, and whether your commercial pages are the easiest to reach.
  • Is it fast and stable for real visitors? Core Web Vitals field data in Search Console, diagnosed with a lab run.
  • Is the markup valid? Structured data errors, hreflang mismatches, broken images, mixed content on HTTPS.

The free tools, and what each is for

ToolFree tierBest at
Google Search ConsoleFree for any site you can verifyThe only source of Google's own data: what is indexed and why not, which queries you appear for, real Core Web Vitals, manual actions. Start here, always
PageSpeed InsightsFree, no accountField data and a lab diagnosis for one URL. Run it on a template, not on your homepage only
LighthouseFree, built into Chrome DevToolsRepeatable local testing while you are actually fixing something, including on staging
Rich Results TestFree, no accountWhether your structured data is valid and eligible for a rich result, tested on the live URL
Screaming Frog SEO SpiderFree up to 500 URLs per crawlThe structural view: status codes, redirect chains, duplicate titles, depth, orphans. Enough for most small sites in full
Ahrefs Webmaster ToolsFree for sites you verify ownership ofA crawl plus a view of your own backlink profile, which the Google tools do not give you
Semrush Site AuditLimited free account, see its pricing pageA scheduled crawl with issue tracking over time, which is what turns an audit into a process

A sensible small business stack is Search Console plus PageSpeed Insights plus one crawler, and that is a complete technical audit capability for nothing.

The 30 minute sequence

  • Minutes 1 to 5. Search Console, Page indexing report. Read the "not indexed" reasons. Anything labelled as excluded by a noindex tag, blocked by robots.txt, or an alternate page with a proper canonical tag that you did not intend is your first ticket.
  • Minutes 5 to 10. Search Console, Manual actions and Security issues. Both should be empty. Ten seconds each, and finding something here changes your whole plan.
  • Minutes 10 to 15. Open your own robots.txt and /sitemap.xml in a browser. Confirm nothing important is disallowed and that the sitemap lists your real pages and nothing you have set to noindex.
  • Minutes 15 to 22. Crawl the site. Sort by status code and fix the 404s and the redirect chains. Sort by title and find the duplicates. Note any page more than three clicks from the homepage that you expect to sell something.
  • Minutes 22 to 27. PageSpeed Insights on three URLs: the homepage, one product or service page, one blog post. One template fix usually covers hundreds of pages.
  • Minutes 27 to 30. Write the ticket list in priority order, with the URL on each line. That list, not the audit, is the deliverable.

Why the score out of 100 is the wrong thing to chase

Every audit tool computes a headline score by counting issues and applying its own weights. Two tools will give the same site two different scores, and both will change when a vendor ships a new release. Google publishes no site score, and a score has never been a ranking signal.

Use the issue list instead, and judge progress on three things: pages indexed against pages you intended to index, Core Web Vitals groups in the good band, and clicks on the pages you fixed. Those are measurements rather than opinions. If a report card helps you get budget approved, show the issue count falling over time and keep the score out of the document.

Where a paid tool earns its money

  • Scale. Above a few thousand URLs, free crawl limits run out and you want scheduled crawls with a diff against last week.
  • Backlink data. Google does not give you a competitor's link profile. This is the clearest reason to pay, and the main vendors publish their own prices: Ahrefs, Semrush and Moz.
  • Competitor visibility. Search Console shows your own site. Anything comparative comes from a third party index.
  • Issue tracking and alerts, so a template that breaks on a Tuesday release does not sit broken for a month.

Questions buyers ask about SEO checker tools

Are free SEO checkers accurate?

For technical checks, yes. A crawler either finds a 404 or it does not. Where free and paid tools differ is coverage, scheduling, and backlink and competitor data, which require a vendor's own crawl of the whole web.

What is a good SEO score?

There is no such target, because each tool invents its own scale. Set your goals as outcomes: every important page indexed, no redirect chains, all Core Web Vitals groups in the good band, every page with a written title and description.

Which single free tool should I use if I only use one?

Search Console. It is the only tool reporting Google's own view of your site, and it covers indexing, queries, clicks, Core Web Vitals, structured data and manual actions in one place.

How often should I run an audit?

Check Search Console weekly for five minutes. Run a full crawl monthly, and immediately after any site migration, theme change, template release or platform upgrade. Those four events cause most sudden technical problems.

Can a checker tell me why my rankings dropped?

It will find the technical causes, which are the ones worth ruling out first: a page fell out of the index, a canonical changed, a template started returning the wrong status, a redirect broke. When the technical side is clean, the answer is on the content and links side, and that is a comparison with the pages now ranking above you.

My checker says I have thousands of issues. Where do I start?

Sort by the priority list at the top of this page and ignore the issue count. Most large numbers come from one template repeated across every page, so the real list is usually five or six fixes.

One check none of these tools performs

Run the free checkers for thirty minutes and you have a list of fixes. What you do not have is the answer a buyer sees when they ask an assistant to recommend someone in your field. That is a different page from the one any checker scored, written fresh for each asker and different in each assistant.

It takes five minutes by hand. Ask ChatGPT, Gemini, Perplexity and Claude the question your best customer would ask, leave your own name out, and note who appears. For a record that repeats across assistants and lists the cited sources, AI Knows Us does the same asking and keeps the results.

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