SEO audit: method, steps and tools

What is an SEO audit?

An SEO audit analyses every factor that shapes a site’s visibility in search engines. It checks three things. Can Google crawl and index the right pages? Do the pages answer real searches? Does the domain inspire trust? It ends with a dated, prioritised action plan, the starting point of any organic search work.

Google describes what an SEO provider can bring. It lists a review of content and structure, technical advice (hosting, redirects, error pages, JavaScript), keyword research and optimisation for generative AI. The list appears on Google’s “Do you need an SEO?” page, updated on June 5, 2026. The audit is the phase that comes before this work.

An audit is not a score out of 100. A tool’s score adds up automated checks without knowing your goals, your history or your market. Google makes the point in its SEO Starter Guide: no recipe automatically puts a site in first position.

What does a full SEO audit cover?

The France Num guide to the SEO audit, published on March 16, 2026, keeps three pillars: technical, content and popularity. Most agency methods use the same split. A fourth angle now joins them: visibility in AI-generated answers.

Area	Question asked	Main data	Detailed guide
Technical	Can Google crawl, render and index the right pages?	Crawl, Search Console, logs, Core Web Vitals	Technical SEO audit
Semantic	Does each page answer one intent, with no duplicates?	Search Console queries, SERPs, content, internal linking	Semantic audit
Backlinks	Is the link profile healthy compared with competitors?	Referring domains, anchors, Links report	Backlink audit
AI visibility	Does the site appear in AI Overviews and assistants?	Search Console generative AI report, query tests	GEO guide

Order matters. As long as the site cannot be crawled and indexed, rewriting pages or buying links produces nothing measurable. Our method runs through three questions: can the site be crawled, can it be indexed, is the technical experience up to standard? Content relevance comes next, then popularity.

How do you carry out an SEO audit, step by step?

1. Scope: business goals, priority pages and queries, perimeter (domain, subdomains, languages). Collect the history of redesigns, migrations and CMS changes: it explains most breaks in the traffic curve.
2. Gather access: Search Console as a domain property, read access to GA4, the back office, server access for logs, a backlink tool. Check how long logs are kept before you plan.
3. Check the blockers: manual action, security issue, indexed staging site. A manual action results from a breach of Google’s spam policies. Until it is lifted, the rest of the audit is pointless.
4. Collect: a full crawl, the Search Console reports and the analytics exports. Add a sample of logs above roughly 1,000 pages.
5. Analyse each area, then cross-check: a page crawled but never visited by Googlebot, a page indexed with no impressions, a page shown often but rarely clicked. Useful findings come from these cross-checks.
6. Prioritise and report: each finding gets an impact, an effort, an owner and a deadline. The deliverable fits into a short summary and an action plan.

Which data sources should you use?

For Google data, start with Search Console: Page indexing, Performance, Core Web Vitals, Security and Manual Actions. On a site with several thousand URLs, log file analysis shows what Googlebot actually visits.

How do you prioritise the recommendations?

Priority	Profile	Examples	Indicative timing
P1 · quick wins	High impact, low effort	Missing titles, accidental robots.txt block, 302s to switch to 301s	Weeks 1 and 2
P2 · structural work	High impact, moderate to high effort	Internal linking, performance, JavaScript rendering	Months 1 to 3
P3 · ongoing optimisation	Moderate impact	Meta descriptions, alt text, weak pages	Months 3 to 6
P4 · optional	Low impact	Finishing touches	After P1 to P3

Do not copy the priority shown by a crawler as it stands. A few URLs still on HTTP can come out as “high priority” there. Yet a redirect chain on category pages costs far more.

Free SEO audit or full audit: which one to choose?

For the query “audit SEO”, five of the top ten Google results are free tools (Elev8 Lab check of September 24, 2026, Google France). They are useful: in two minutes they spot a missing title tag, a slow page, an expired certificate.

Their limit comes from how they are built. An online tool analyses one page or a sample, with no access to your Search Console, your logs or your goals. It does not know whether a noindex page is noindexed on purpose, or whether the drop in traffic follows a migration.

Criterion	Free audit tool	Full SEO audit
Scope	One URL or a sample	The whole site, template by template
Data	External crawl	Crawl, Search Console, analytics, logs, backlinks
Reading	Score and generic alerts	Findings tied to your goals
Deliverable	List of alerts	Prioritised action plan
Recommended use	First check, monitoring	Traffic drop, redesign, budget decisions

How much does an SEO audit cost and how long does it take?

There is no reliable public price scale for an SEO audit in France. The ranges that circulate specify neither the scope nor the deliverable: they do not let you compare two quotes.

Four factors set the price and the duration:

• the number of pages and templates;
• whether there are logs or international versions;
• the number of areas covered;
• the reporting format: a summary for management, tickets for the technical team.

A serious quote specifies:

• the exact scope: domains, languages, number of URLs crawled;
• the data sources used;
• the format of the deliverable and whether it includes a prioritised action plan;
• the support planned after delivery.

Google advises asking the provider for examples of past work. It also suggests asking about the expected results, how long they will take and how success will be measured. Our approach is described on the SEO and GEO services page.

What should you do after the SEO audit?

An audit is only worth what its execution delivers. A short roadmap carried through brings more than a 200-point report that is never applied. Secure the budget for fixes before launching the audit.

Track a small number of indicators, measured before the fixes and then at fixed intervals:

• indexed pages compared with expected pages;
• crawl errors, to bring down towards zero;
• Core Web Vitals: LCP up to 2.5 s, INP up to 200 ms, CLS up to 0.1, measured at the 75th percentile (Google documentation);
• non-brand organic traffic;
• click-through rate of the pages whose tags were rewritten.

For frequency, we apply an agency convention, not a Google rule. A quarterly re-audit above 10,000 pages or for e-commerce, every six months between 1,000 and 10,000 pages, yearly below that. Between two audits, alerts (Search Console, rankings, Core Web Vitals) take over.

Should an SEO audit cover AI engines?

Yes, at least through a check. On June 3, 2026, Google announced a generative AI performance report in Search Console, extended to all countries on August 31, 2026. It gives impressions, pages, countries, devices and dates, but not queries, clicks or position.

In an audit, this area checks three points:

• AI crawlers are not blocked by mistake, in robots.txt or in the CDN settings;
• key pages give direct, sourced answers;
• the brand is described consistently from one page to the next.

The core requirements do not change: Google asks for helpful, reliable content made for people first, as its guide on helpful content explains. A well-run SEO audit therefore also prepares the ground for AI answers.