SEO checker: what your site is worth, and what to fix first

You run a blog, a small shop or a business site, and you wonder what it’s worth in Google’s eyes. An SEO checker answers that. The catch is knowing which one to run, and what to do with the score it gives you.

This page shows you a real check, run on October 29, 2026 on plugkit-avis.com, one of my sites, then the free tools that check each part on their own. Facts about other tools come from their own pages, read and dated. Links to SemChat are affiliate links: they don’t change your price or what I report.

Website SEO checker: what a check of your site looks at

Search for “seo checker” in the United States and Google’s first page is mostly free online tools: you paste an address, you get a score. Behind the score, every website SEO checker looks at the same four things.

• Technical health: can Google read your pages? Errors, missing pages, slow loading, mobile version.
• Content: do your pages use the words your customers type? A clear title, a description, a text that answers.
• Links: do other sites mention you? Do your own pages link to each other?
• Visibility: which searches you show up for, at what position, with how many clicks.

Google describes its own work in three stages: crawling, indexing, and serving search results. It is blunt about one thing: it doesn’t accept payment to crawl a site more often or rank it higher (Google’s “How Search works” page, read October 30, 2026). A check is there to confirm your site gets through each stage.

One page or the whole site: what a checker reads

Two kinds of checks, two uses.

• A one-page check: one address, one score, a list of points. You just published a page and want to check its title, description and headings. Free online checkers do this well.
• A whole-site check: every page, your rankings, your links, your competitors. That’s what you need when traffic drops for no clear reason, or before a redesign. Here a score isn’t enough: you need an order of priority.

Seobility’s own checker is honest about the difference: its free version reads one address, and analyzing “more than a single URL” takes its paid Premium plan (page read October 30, 2026).

Google’s own free check: Search Console

Search Console is the only check built on Google’s own data. Its page puts it this way: “Search Console tools and reports help you measure your site’s Search traffic and performance, fix issues, and make your site shine in Google Search results.” Its help center adds that it’s a free service (Google pages read October 30, 2026).

Google’s Search Console overview page. Screenshot of search.google.com/search-console/about, taken October 30, 2026.

It doesn’t give you one score. It gives you reports. Open three of them, in this order:

1. Page indexing: which of your pages Google can find and index, and the indexing problems it ran into. If an important page is missing here, nothing else matters yet.
2. Performance: your searches, clicks and impressions. Sort by impressions: a search where you show up often but rarely get clicked calls for a better title.
3. Links: the sites that link to you the most, and your most linked pages.

Good to know: Google’s help says you don’t have to sign up for Search Console to be included in Google Search results. It helps you understand your site, not exist in Google.

SEO score checker: what your score means, and what it hides

A score out of 100 is reassuring. It’s also easy to misread. A score usually counts the problems the tool checks for, and only those. A page can score well and still lose to a competitor that answers the question better.

A high score with real problems: an example

The clearest example came from SemChat itself. After the audit, SemChat creates a record for the site. Its Health tab (the interface is in French) gave plugkit-avis.com a score of 99, “excellent shape,” nothing urgent to fix. The same audit found duplicate titles on 100 pages, 53% of the site.

SemChat’s Health tab rates the site in excellent shape, nothing urgent to fix. Screenshot of the SemChat app, October 29, 2026 (French interface).

Both are true. The Health score checks for broken pages, pages without a title or without links. It doesn’t check for pages that look too much alike. I checked the duplicate titles with curl the same day: they were real between the US English and UK English versions. But those pages are declared to Google as language variants (hreflang tags), so calling them “mirror pages” went too far. The flag was useful; the wording was too strong.

The lesson for any SEO score checker: read the list behind the score, not just the number.

SEO website analyzer or SEO test: which one you need

If you just want a quick score on one page, an online SEO test is enough. If you want to know what to fix across the site, you need an SEO website analyzer that crawls every page and ranks the problems.

Free SEO checkers: Seobility, Semrush and the others

Here is what each tool’s own page says, read October 29 and 30, 2026:

Seobility’s free SEO Checker page. Screenshot of seobility.net/en/seocheck, taken October 30, 2026.

None of these is wrong to use. They answer a narrower question than a full audit: is this page in good shape?

A five-minute SEO test you can run yourself

No tool can tell you what your page is missing compared with the pages that beat it. You can, in five minutes:

1. Search Google for the query your page targets.
2. Open the top three results.
3. Write down what they cover that your page doesn’t: a question, a table, an example, a price.
4. Compare their titles with yours: which one would you click?

On plugkit-avis.com, that kind of gap is exactly what the audit pointed to: a comparison page of 495 words, thinner than competing pages, where SemChat suggested a summary table. A checker that hunts for errors has little to say about a page like that: nothing on it is broken, it’s just thinner than the competition.

Browser extensions for a quick check

To check a page while you browse, two extensions come up in the tools’ own pages. Ahrefs’ SEO Toolbar is free for Chrome, Firefox and Safari: it shows a page’s structure, its outgoing links, its indexability and redirects; its authority scores need a free Ahrefs account (SEO Toolbar page, read October 29, 2026). Ubersuggest’s free Chrome extension shows keyword volume and competition right in Google, with 40 searches a day on a free account (Ubersuggest help, updated July 26, 2025).

Demo: a full check in one sentence with SemChat

SemChat is a conversational SEO assistant: you type a request, it runs its analysis tools and answers in plain words. One thing to know first: my test was in French, on a French site, and SemChat’s data tools were set to France. How it handles an English site in the US is something I haven’t tested.

On October 29, 2026, on the Free plan, I opened a new chat and typed one sentence in French. In English, it reads: “Run an SEO audit of my site plugkit-avis.com and give me a clear action plan, by priority.”

SemChat picked its own procedure, “Full SEO Audit.” It read the pages, crawled the whole site, pulled 89 rankings, 30 top pages, the backlink profile and 10 competitors, then compared the site with 5 of them. About 3 minutes later, the action plan was there. My full test of the tool, mistakes included, is in my SemChat review.

The indicators it returned

The answer opens with a grid of 8 key figures. These are SemChat’s numbers as it showed them:

The key indicators returned at the end of the check of plugkit-avis.com. Screenshot of the SemChat app, October 29, 2026 (French interface).

Each step has a “see details” button that opens the raw data, with a CSV export. So you can check where a number comes from. I’d do that for estimated traffic and search volumes before acting on them.

The diagnosis and this week’s actions

The diagnosis had 5 points: a solid base for a site under two months old, duplicate titles caused by the language versions, an opportunity on “manychat” (9,000 searches a month according to SemChat, a figure I didn’t cross-check) and searches captured by competitors. Then 3 actions for the week:

1. Create the /fr/contact/ page, which returned a 404 error.
2. Add the language to each title to break the duplication.
3. Expand the comparison page, 495 words, with a summary table.

I checked with curl the same day: the contact page did return a 404. The check also ends with a 10-section “Full SEO Audit” document you can copy or download.

What the check cost: 100% of the Free quota

Here’s the limit to know. This one check used 100% of the Free plan’s monthly quota: 39.2% on documents, 32% on site analysis, 28.9% on SEO tools. The counter reset on November 28.

The Usage screen after the check: the Free plan quota is used up. Screenshot of the SemChat app, October 29, 2026 (French interface).

So on the Free plan, count on one full check a month, on your main site. SemChat’s pricing page says “Try semchat with no credit card”; the next plan, Starter, costs €20 a month excluding tax (page read October 30, 2026). Plan details and top-ups are on my SemChat pricing page.

What to fix first after any check

Whatever SEO checker you use, you’ll get a list. Sort it yourself in this order:

1. What blocks Google: pages with errors, pages not indexed, a site that’s slow on mobile. PageSpeed Insights, Google’s speed test, calls a score of 90 or above good, 50 to 89 in need of improvement, and below 50 poor. It also shows three Core Web Vitals: how fast the largest element appears (good up to 2.5 seconds), how fast the page reacts to a tap (good up to 200 milliseconds) and how stable the layout stays (good up to 0.1). Thresholds from its documentation, read October 30, 2026.
2. What earns the click: titles and descriptions of your most viewed pages in Search Console. To see the searches that already bring you visits, and the ones you’re missing, check website keywords.
3. What keeps people reading: the content of pages that get visits but no customers.
4. What gets you recommended: links from other sites, which take the longest.

A long list with no order is twenty reasons to do nothing. A useful check gives you the first fix for this week, and you run it again next month to see if the fixes worked.

An SEO checker is only worth something if it leads to one fix this week.

The pages below go through each part of the check, from the free audit to tracking your rankings.