The Complete SEO Audit Checklist for 2025

An SEO audit is a systematic examination of your website's ability to appear in search engine results. It identifies technical barriers, content gaps, and missed opportunities that prevent your pages from ranking as well as they should. Without a structured audit, you are guessing at what needs fixing.

This checklist is organised into three categories: technical SEO, on-page SEO, and off-page SEO. Work through each section methodically. The goal is not to check every box in a single day but to identify your highest-priority issues and address them in order of impact.

Part 1: Technical SEO Audit

Technical SEO is the foundation. If search engines cannot efficiently crawl, index, and render your pages, no amount of content optimisation will compensate. Start here.

Crawlability and Indexing

Open Google Search Console and review the Pages report (formerly Coverage). This shows which pages Google has indexed, which it has excluded, and why. Pay attention to pages with "Crawled -- currently not indexed" status, as these indicate Google found the page but chose not to index it, often a content quality signal.

• Check your robots.txt: Verify it is not accidentally blocking important pages or resources. Use the robots.txt Tester in Search Console.
• Review your XML sitemap: Ensure it includes only indexable, canonical URLs. Remove pages that return 404 errors, redirects, or noindex directives. Submit the sitemap through Search Console.
• Check for orphan pages: Use a crawler like Screaming Frog to identify pages that exist on your site but are not linked to from any other page. Orphan pages are difficult for search engines to discover.
• Review canonical tags: Every indexable page should have a self-referencing canonical tag. Check for conflicting signals where the canonical points to a different URL than the one being served.

Site Speed and Core Web Vitals

Google uses Core Web Vitals as a ranking factor. The three metrics that matter are Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS). Check your site's performance using PageSpeed Insights, which provides both lab data and real-user field data from the Chrome User Experience Report.

• LCP target: Under 2.5 seconds. The most common causes of poor LCP are unoptimised images, slow server response times, and render-blocking CSS or JavaScript.
• INP target: Under 200 milliseconds. Heavy JavaScript execution and long main-thread tasks are the primary causes of poor INP.
• CLS target: Under 0.1. Set explicit width and height on images and embeds, and avoid dynamically injecting content above existing content.

Mobile Usability

Google uses mobile-first indexing, meaning the mobile version of your site is what Google primarily crawls and indexes. Check the Mobile Usability report in Search Console for issues such as text too small to read, clickable elements too close together, and content wider than screen. Test key pages manually on actual mobile devices, not just browser emulators.

HTTPS and Security

Your entire site should be served over HTTPS with a valid SSL certificate. Check for mixed content warnings where HTTPS pages load resources (images, scripts, stylesheets) over HTTP. Use the Security Issues report in Search Console to identify any flagged problems.

Part 2: On-Page SEO Audit

On-page SEO covers everything visitors and search engines encounter on your actual pages. This is where content quality, keyword targeting, and user experience intersect.

Title Tags and Meta Descriptions

• Title tags: Every page needs a unique, descriptive title under 60 characters. Include the primary target keyword naturally. Avoid keyword stuffing and generic titles like "Home" or "Services."
• Meta descriptions: Write unique descriptions under 160 characters for every key page. While meta descriptions do not directly affect rankings, they influence click-through rates from search results, which can indirectly affect performance.
• Check for duplicates: Run a crawl to identify pages sharing the same title tag or meta description. Each page should have unique metadata.

Header Structure

Each page should have exactly one H1 tag that clearly describes the page's topic. Use H2s for major sections and H3s for subsections within those. Headers should form a logical hierarchy that helps both users and search engines understand the content structure. Avoid skipping levels (going from H1 directly to H3) and avoid using headers purely for styling.

Content Quality and Depth

Review your most important pages against the competition. Search for your target keywords and compare your content with the top-ranking results. Ask whether your content is as comprehensive, more useful, and more current than what already ranks. Look for thin pages — those with very little substantive content — and either improve them or consolidate them with related pages.

Check for keyword cannibalisation: multiple pages on your site targeting the same keyword. When this happens, Google has to choose which page to rank, and it may not choose the one you prefer. Use Search Console's Performance report to identify cases where multiple URLs receive impressions for the same query.

Internal Linking

Internal links help search engines understand site structure and distribute ranking authority across your pages. Review your most important pages and ensure they receive internal links from other relevant pages. Use descriptive anchor text that tells both users and search engines what the linked page is about. Avoid generic anchor text like "click here" or "read more."

Image Optimisation

• Alt text: Every image should have descriptive alt text that explains what the image shows. This is essential for accessibility and helps images appear in Google Image Search.
• File size: Compress images appropriately. Use modern formats like WebP or AVIF where supported. Serve responsive images using srcset attributes.
• File names: Use descriptive file names rather than generic ones like "IMG_1234.jpg."

Structured Data

Implement relevant structured data (Schema.org markup) to help search engines understand your content and potentially display rich results. Common types include Article, FAQ, Product, LocalBusiness, and BreadcrumbList. Validate your markup using Google's Rich Results Test and monitor the Enhancements reports in Search Console.

Part 3: Off-Page SEO Audit

Off-page SEO encompasses factors outside your website that influence your rankings, primarily your backlink profile and online reputation.

Backlink Profile Analysis

Use a tool like Ahrefs, Semrush, or Moz to review your backlink profile. Focus on the quality and relevance of linking domains rather than raw numbers. A handful of links from authoritative, relevant websites is worth more than hundreds of links from low-quality directories or unrelated sites.

• Identify toxic links: Look for links from spammy, irrelevant, or penalised sites. If you find a significant number, consider using Google's Disavow Tool — but use it cautiously and only for clearly harmful links.
• Analyse competitor backlinks: Review where your top-ranking competitors are earning links. This can reveal link-building opportunities you are missing, such as industry directories, resource pages, or publications that cover your sector.
• Check for lost links: Identify valuable backlinks you have lost recently and investigate whether the linking page was removed, the content changed, or the link was replaced.

Local Citations (for Local Businesses)

If your business serves a specific geographic area, ensure your Name, Address, and Phone number (NAP) are consistent across all online directories, your Google Business Profile, social media profiles, and your website. Inconsistent NAP information confuses search engines and can hurt local rankings.

Online Reputation

Google's quality rater guidelines emphasise reputation as a component of trust. Monitor your reviews on Google Business Profile, industry-specific review sites, and social media. Respond to reviews — both positive and negative — professionally. A pattern of unaddressed negative reviews can signal trust issues to both potential customers and search engines.

Prioritising Your Fixes

An SEO audit will almost always uncover more issues than you can fix at once. Prioritise based on impact and effort. Critical technical issues — such as pages being blocked from indexing, broken canonical tags, or severe Core Web Vitals failures — should be addressed first because they affect your entire site's ability to rank. On-page improvements to your highest-traffic pages come next, followed by off-page and lower-priority optimisations.

Document everything. Create a spreadsheet with each issue, its priority level, the affected URLs, and the specific fix required. Track your progress and re-audit quarterly to ensure issues do not recur and to catch new ones early.