Semrush · Site Audit
Semrush Site Audit, and the limit you hit on the first run
Part of the Semrush tool listing, 18 in-depth guides plus the full review.
The short answer
Site Audit is a crawler with a reporting layer on top. You point it at a domain, it fetches pages up to your plan's crawl limit, and returns issues split into errors, warnings and notices plus thematic scores. It is good enough to be your scheduled health check. It stops at the crawl cap, it does not render JavaScript unless you switch that on, and it reports what it could fetch rather than what Google actually fetched.
Semrush sells Site Audit on the number of checks it runs. That number is not the useful part, and it is not what goes wrong.
What goes wrong is that the crawl stops early, the score rewards you for the wrong things, and the report describes what Semrush could fetch rather than what Google actually did. I have run this on my own sites and on client sites for years, and all three of those bite on the first run.
What the crawl actually does
You give it a domain, choose a source (the site itself, a sitemap, or a URL list), set a page cap, and optionally switch on JavaScript rendering. It fetches, then sorts what it found into errors, warnings and notices, plus thematic scores for crawlability, HTTPS, internal linking, markup and Core Web Vitals.
The setup screen lets you cap the crawl yourself, at 1,000, 5,000, 10,000, up to 100,000 or a custom number. If you don’t know what to pick, 1,000 is a sane first run because it finishes fast enough that you’ll actually read it.
The limit you hit on the first run
Here’s the part no feature list mentions. On camera, my crawl finished and Semrush put up a warning that it had reached the limit, having found more pages than it was allowed to fetch. Not a failure. Just an audit of part of my site presented with the same confidence as an audit of all of it.
That ceiling is a plan ceiling, which means your technical audit is scoped by your subscription. On a site of any real size, the first honest question about a Site Audit report is not “what did it find”, it is “what fraction of the site is this”. Check which tier you are on and what it allows before you act on a prioritised list that might be prioritising a third of your pages.
The health score is not a grade
Site health is a weighted count of issues divided by checks passed. It is not a judgement about whether your site does well in search, and treating it as one produces busywork.
In that same audit, crawlability sat at 92 percent while Core Web Vitals was the thematic report actually failing. It also flagged 96 pages with unminified JavaScript and CSS. Minification is real, and it is also the kind of finding that inflates an issue count without changing a ranking, while the one section that genuinely affects users sat below it.
Read the thematic reports, then read the errors. Ignore the number at the top. If you want the score to go up, fix notices. If you want the site to get better, fix the theme that’s failing.
What Site Audit cannot see
It is a crawler. It reports what its own fetcher could reach, and that is a different thing from what Googlebot reached.
Two consequences worth knowing:
JavaScript rendering is a toggle you have to find. It’s in the crawl setup with an explanation beside it, and it isn’t on by default in the flow. Audit a JavaScript-heavy site with it off and you have audited an HTML skeleton.
Crawl budget is invisible here. No crawler can tell you whether Google is actually visiting your important pages or burning requests on parameter URLs. That’s what the Log File Analyzer is for: you upload your raw server logs and it maps what Googlebot really requested and how often. It’s the least glamorous tool in Semrush and the only one that verifies the assumption every audit rests on.
When you want the On-Page SEO Checker instead
These two get confused constantly, and they answer different questions.
Site Audit asks: is anything broken across this site? On-Page SEO Checker asks: for this one page and this one target keyword, what are the top ten results doing that I’m not? It pulls semantic terms, backlink ideas and content-length comparisons for a single URL.
So the workflow is: Site Audit on a schedule to catch what breaks, On-Page SEO Checker on the specific page you’re trying to move. Running the second one as a site-wide strategy is how people end up with a hundred pages of TF-IDF suggestions and no ranking changes.
If the crawl is genuinely all you came for, a dedicated crawler is both cheaper and deeper. Screaming Frog is free to 500 URLs and costs less per year than two months of a Semrush mid tier.
What this looks like on screen
Each clip opens at the minute the thing above happens, not at the start of the recording.
Questions
How many pages can Semrush Site Audit crawl?
It depends on the plan. The crawl setup lets you cap it yourself, up to 100,000 or a custom figure, but the ceiling is set by your tier. On a mid plan a mid-sized site can hit the cap on the first run, and Semrush tells you when it does.
Is the Semrush site health score reliable?
It is a weighted count of the issues Semrush found, not an assessment of how your site performs in search. A site can score in the nineties with failing Core Web Vitals, because the score counts issues rather than weighing consequences. Read the thematic reports instead.
Does Semrush Site Audit render JavaScript?
Only if you enable JavaScript rendering when you configure the crawl. It is a toggle in the setup, off by default in the flow. Leave it off on a JavaScript-heavy site and the audit describes a version of your pages that visitors never see.
What is the difference between Site Audit and the On-Page SEO Checker?
Site Audit crawls the whole site for technical problems. The On-Page SEO Checker takes one page and one target keyword and compares your on-page work to the top ten ranking results. Different input, different question, and neither replaces the other.
Sources
Each one says which claim on this page it stands behind, and when it was read.
- Semrush pricing page Verifies plans, limits · read 20 August 2026
- Semrush knowledge base Verifies features · read 20 August 2026
Where to go next
- Semrush: the full listing What it does, what it costs, and what it cannot do, with every field dated.
- What Semrush costs, and which reports are locked where The crawl limit is a plan limit. This is where the plan limits are.
- The Semrush tutorial, every tool in workflow order The rest of the toolkit, in the order you would actually use it.
- Screaming Frog SEO Spider If the crawl is the only thing you need, this is cheaper and goes deeper.
- The full Semrush listing Every field, with the date it was checked.