How to do an SEO audit, and the best tools for it

Start every audit here. Google Search Console is a free service from Google, and it reports from inside Google rather than guessing from the outside. The Page indexing report lists every URL Google knows about, split into indexed and not indexed, with the reason for each exclusion: blocked by robots.txt, excluded by a noindex tag, duplicate without a user-selected canonical, soft 404, "Crawled, currently not indexed" and "Discovered, currently not indexed".

The URL Inspection tool is the one to learn first. Paste any address and it shows Google's indexed version of that page, the canonical Google picked, and whether the live URL could be indexed today. When a crawler and Search Console disagree, believe Search Console. The Performance report adds clicks, impressions, CTR and average position per query and per page, which is how you find pages that rank on page two and only need a better title.

Its limits are real. It works on sites you verify, so competitor audits are out. It never crawls your site on demand like Screaming Frog does: it reports what Googlebot happened to see, with a delay. And it says nothing about backlinks beyond a sample. Pair it with a crawler and you have a complete free audit for a small site.

Screaming Frog is the crawler most audit guides open with, and for good reason. It runs on your computer, follows every link like a search engine bot, and gives you one row per URL: status code, title, meta description, H1, canonical, meta robots, word count, inlinks, crawl depth. Broken links, redirect chains, duplicate titles and orphan pages all come out of that table.

The free version crawls up to 500 URLs. Above that you need a licence at $279 per licence, per year, and licences are per user: two people auditing means two licences, $558 a year. That is about $23 a month for one user, far below any cloud suite. The paid licence also unlocks what the free version lacks for serious work: saving and reopening crawls, JavaScript rendering, crawl comparison, and the Google Analytics, Search Console and PageSpeed Insights integrations.

The learning curve is steep. The interface is a wall of tabs and filters, and nothing tells you which of 300 warnings matters. Large crawls depend on your machine's memory: switch to database storage mode before crawling a site with hundreds of thousands of URLs. If you want issues explained and ranked for you, Sitebulb does that better.

Ahrefs Webmaster Tools, now renamed Ahrefs Free, is the free tier of Ahrefs, and for an owner it is the most generous free audit we compared. You get 5,000 crawl credits per verified project per month, on an unlimited number of verified websites. Site Audit checks more than 170 technical and on-page issues, and Site Explorer shows which pages and keywords bring organic traffic and who links to you.

Here is the detail most guides skip: credits are only used when the crawler hits an HTML page that returns a 200 status. Redirects, 404s, images and scripts do not eat your allowance. A site with 4,000 live pages and thousands of old redirected URLs still fits in one monthly crawl.

The catch is verification. Like Search Console, it only audits sites you can prove you own, so competitor analysis needs a paid plan. Starter, at $29 a month, opens competitor research; auditing a site you do not own starts with Lite, at $129 a month or $1,290 a year (about $108 a month), which covers 5 unverified projects. Ahrefs does not issue refunds in general, so try the free tier for a full month before you subscribe. To weigh it against the other big suite, read our Semrush vs Ahrefs comparison.

Semrush is the tool all five audit guides we read mention, usually through its Site Audit. You set up a project, the crawler runs, and you get a Site Health score with issues split into errors, warnings and notices. Around it sit the rest of an audit: Keyword Gap against competitors, the Backlink Audit, Position Tracking and the On Page SEO Checker.

The free account is narrow: 100 pages per month for Site Audit, total, not per audit. One crawl of a 300-page site stops at 100 and uses your whole month, until the reset on the first of the next month. The SEO plan costs $139.95 a month, or $117.33 a month billed yearly ($1,407.96 a year), and each additional user starts at $45 a month. A team of three on monthly billing pays at least $229.95 a month.

Do not chase the Health score. It is computed from the total number of errors and warnings found on the crawled pages, with errors weighing more, not from what each issue costs you in traffic: a hundred warnings on pages nobody visits can weigh on it more than one error on your best page. Read errors first, then decide. More detail in our Semrush review and Semrush alternatives, and to learn Site Audit and the rest of the suite, our Semrush training guide.

Sitebulb crawls like Screaming Frog but reads like a report. Each issue comes with a priority, an explanation of why it matters and how to fix it: 100+ hints on Lite, 300+ on Pro. Crawl maps draw your architecture, so a cluster of pages five clicks deep jumps out at once. For a first audit, or for handing findings to a client, that guidance saves hours.

Lite costs $18 a month and covers 10,000 URLs per audit. Pro costs $42 a month and goes up to 500,000 URLs per audit, with 300+ hints instead of 100+ on Lite, audit comparison and scheduled audits. Crawl maps and JavaScript crawling come with both plans. Yearly billing saves 15%: Lite drops to $180 a year instead of $216 on monthly billing. There is a 14 day free trial.

Like Screaming Frog, Sitebulb Pro is desktop software that runs on Windows or Mac, so your laptop's memory caps what you can crawl. It has no keyword or backlink data at all: it is an audit crawler, nothing else. Sitebulb Cloud removes the machine limit but starts at $125 a month. Compare all crawlers in our best SEO crawler ranking.

SE Ranking is the suite that gives the most audit capacity for the money. Core costs $129 a month, or $103.20 a month on yearly billing, and includes 10 projects, one manager seat, 2,000 keywords tracked daily and 250,000 pages per month in the website audit. Growth, at $279 a month, raises that to 2 million audit pages and 30 projects.

For an audit, that means you can crawl ten client sites of 20,000 pages each every month on the entry plan, where the Semrush free account stops at 100 pages. The audit groups issues by category and recrawls on a schedule, and rank tracking runs in the same project, so you can check whether a fix moved positions.

Its limits: the backlink database is smaller than Ahrefs or Semrush, and the interface packs a lot into each screen. There is a free 14-day trial, no credit card required. To send project data to other tools, see the SE Ranking integration for Make. If you are leaving it, our SE Ranking alternatives page covers the options.

PageSpeed Insights is Google's free speed tool, and it shows two different things that people mix up. The top block is field data: how real Chrome users experienced the page over the previous 28-day collection period, at the 75th percentile. The bottom block is lab data: Lighthouse analyzes the URL in a simulated environment and lists what to fix.

Only field data counts for Core Web Vitals. A page passes when LCP is 2.5 seconds or less, INP 200 milliseconds or less, and CLS 0.1 or less. Because field data is a trailing 28-day window, a fix you ship today can take up to four weeks to turn the report green. Do not panic when the lab score jumps around from one run to the next: that is the simulation, not your users.

It tests one URL at a time and gives no crawl. For a site-wide view, use the Core Web Vitals report in Search Console, then run PageSpeed Insights on one representative URL per template (home, category, product, article).