An SEO audit is the equivalent of a health check for your website. Without one you are working blind: a single technical error can stop dozens of pages being indexed, and a duplicate content problem can halve your organic traffic. In 2026, Google is more demanding than ever about technical quality and content.
At ConvertiLab, we run an SEO audit on every site before launching a search strategy. Across our 150+ audited clients, 78% had at least one critical technical error blocking their indexing. Start with our free SEO audit to get your diagnosis in 2 minutes.
Why run an SEO audit and when should you do it?
An SEO audit identifies the technical errors blocking indexing, uncovers untapped keyword opportunities, assesses the quality of your backlink profile, and prioritises the work so you get the most return. It is essential before launching an SEO strategy (so you start on solid ground), after a site rebuild (to check nothing has broken), when traffic drops suddenly (an emergency diagnosis), and every 6 months as routine monitoring.
When an SEO audit should be your priority:
How do you run the technical audit of your website?
The technical audit is the foundation of good SEO: a technically broken site cannot rank well. It breaks down into 4 parts: crawling the site (error pages, redirects, duplicate content), checking indexing in Google Search Console, information architecture (navigation depth, internal linking), and HTTPS security. The essential tool: Screaming Frog (free up to 500 pages) to crawl your site in 5 minutes. For an even quicker audit, our SEO Check tool on convertilab.com automatically analyses the 20 most critical technical points and generates a PDF report with the work prioritised.
A technical crawl with Screaming Frog reveals:
In Google Search Console, check:
How do you audit your site's performance and user experience?
To audit performance, test your key pages with Google PageSpeed Insights (free), which measures the 3 Core Web Vitals: LCP (main content load, threshold under 2.5s), INP (responsiveness to interactions, threshold under 200ms), and CLS (visual stability, threshold under 0.1). These 3 metrics have been official ranking factors since 2021. A site with Core Web Vitals in the red loses positions to competitors that are technically equivalent but faster. Always test the mobile version: since 2023 Google has used the mobile-first index exclusively, which means your mobile score is the one that counts for your ranking, whatever your desktop performance.
Speed factors to check, in order of priority:
How do you analyse content and backlinks in an SEO audit?
A content audit means listing every page and sorting them into 4 categories: keep and improve (good content with room to grow), merge (several weak pages on the same subject), update (dated content on a subject that still matters), delete or deindex (content with no SEO value). For backlinks, analyse them with Ahrefs or Google Search Console: the number of referring domains, the dofollow to nofollow ratio, the authority of those domains, and any toxic links to disavow.
An action plan after the audit, 3 priorities:
Quick wins (1-2 weeks):
Medium term (1-3 months):
Long term (3-12 months):
A real ConvertiLab example: an estate agency in Montpellier had watched its organic traffic fall 40% in 3 months without understanding why. The audit found two causes: a robots.txt generated during a rebuild that was blocking 60% of the pages, and a redirect loop on the town pages. Fixed in 2 days. The result: traffic was back to its original level in 5 weeks, without writing a single line of content. That is the power of a technical audit: finding the invisible problems that cost thousands of visits a month.
The 5 internal linking mistakes that sabotage your SEO
Internal linking (the links between your own pages) is often overlooked in audits, even though it directly influences how much authority your pages carry and how deeply Google explores your site. Here are the 5 most common mistakes:
Frequently asked questions about SEO audits
How much does a professional SEO audit cost?
The price of an SEO audit varies with the size of the site and the depth of the analysis. For a site of fewer than 100 pages, allow between 500 and 1,500 euros. For an e-commerce site with several thousand pages, the cost can reach 3,000 to 5,000 euros. Our free SEO audit gives you a first automated diagnosis in 2 minutes, identifying the critical problems at no cost.
Can I run an SEO audit myself?
Yes, with the right tools and this guide you can run a basic audit. Google Search Console (free) and Screaming Frog (the free version covers 500 URLs) are enough for the fundamentals. A professional audit does add interpretation and strategic recommendations that the tools alone cannot provide, in particular when it comes to prioritising the work by its impact in your specific sector.
How often should you run a complete SEO audit?
A complete SEO audit is recommended every 6 to 12 months. In between, check your key indicators in Google Search Console monthly (indexing errors, search performance). After a site rebuild or an unexpected drop in traffic, an emergency audit is essential so you can find the cause quickly.
What is the difference between a free SEO audit and a professional one?
A free SEO audit (like our tool on convertilab.com) automatically analyses the major technical signals: speed score, indexing, title and meta tags, HTML structure, HTTPS. It identifies the obvious problems in 2 minutes. A professional audit adds a manual analysis of search intent, a competitor study, a map of keyword opportunities, and recommendations prioritised by their impact on your business goals. For a first snapshot of where you stand, the automated audit is enough. To build a strategy, the professional audit is essential. !Free versus professional SEO audit - automatic and manual analysis keywords competitors
