This meta tag checker fetches a page the way a crawler does and reads the tags that decide how it appears in search and in shared links: the title tag, the meta description, robots directives, the canonical tag, viewport, language, favicon, Open Graph and Twitter tags. It works as a title tag checker, a meta description checker and a SERP preview tool in one pass, and you can edit the title and description in place to test new versions.
What the checker looks at
| Tag | Why it matters | What we flag |
|---|---|---|
| Title | Main source for the blue title link in results | Missing, under 30 or over 60 characters, more than one |
| Meta description | Often used as the snippet under the title | Missing, under 70 or over 160 characters, duplicates, same as title |
| Robots and X-Robots-Tag | Controls indexing and snippets | noindex, nosnippet, max-snippet:0 and other restrictive rules |
| Canonical | Tells Google which URL you prefer to index | Missing, more than one, pointing to another URL or domain |
| Viewport, lang, charset, favicon | Mobile rendering, accessibility, result display | Missing or incomplete values |
| Open Graph and Twitter | Link previews in social and chat apps | Missing title, description, image or card type |
How long should a title tag and meta description be?
Aim for a title of about 30 to 60 characters and a description of about 70 to 160 characters. These are display limits, not rules: Google says there is no length limit for either, but results are truncated to fit the device width (title links, snippets). Put the words that matter first so a cut costs nothing.
The same documentation explains that Google may rewrite either one. Titles that are long, repetitive across a site or packed with keywords are the usual candidates, and descriptions are replaced when page text answers the search better. Our view: write the description as a short pitch for the page, since its job is to earn the click rather than to rank.
Reading the SERP preview
The preview measures text in pixels, the way the result layout does, rather than counting characters. Titles are measured in 20px Arial against about 600 pixels on desktop; descriptions in 14px Arial against about two lines (920 pixels). The mobile view uses a narrower column where titles can wrap. When a line is cut you will see an ellipsis, and the counters above each field turn amber or red. Type into either field and the preview, the checklist and the tags to paste all update together, which makes it easy to compare a few versions before you change the page.
The site name and breadcrumb line come from your WebSite structured data or og:site_name when present, then the hostname. If you have not set them, our schema markup validator shows which structured data the page already has.
Robots directives in plain English
The checker reads both the robots meta tag and the X-Robots-Tag HTTP header, which is easy to miss because it never appears in the HTML. The rules that change what searchers see most often:
- noindex removes the page from results. See noindex.
- nosnippet and max-snippet:0 remove the text preview. Google says this also keeps the content from being used as a direct input for AI Overviews and AI Mode (robots meta tag reference).
- max-image-preview:large allows large image previews, which Google recommends for Discover.
- noarchive no longer has a visible effect in Google, which stopped showing cached pages.
Methodology and limits
We request the URL once from our server with a standard crawler user agent, follow up to five redirects, and parse the returned HTML without running JavaScript. A canonical counts as self-referencing when it matches the final URL after redirects, ignoring a trailing slash. Results reflect what the server sent at that moment: pages behind a login, a bot challenge or geo-restrictions may look different to Google. The preview is an approximation of Google's layout, which changes over time and varies with the query, so treat pixel limits as a guide.
Tags are only part of on-page SEO. For the wider list, work through the technical SEO checklist, or check whether the copy itself is repetitive with the keyword density checker.
Frequently asked questions
- Is the meta description a ranking factor?
- No. It shapes the snippet people read before they click, so it affects click-through rather than position. Google often replaces it with page text when that text matches the search better.
- Why does Google show a different title from my title tag?
- Google builds the title link from several sources, including the title element, the main visible heading, other prominent text and anchor text. It tends to replace titles that are very long, stuffed with keywords, repeated across many pages, or that do not describe the page.
- Do I still need Open Graph and Twitter tags?
- Yes, if your pages get shared. Search engines do not rank on them, but Facebook, LinkedIn, Slack, X and most messaging apps build their link previews from og:title, og:description and og:image.
- Can this tool check pages that need JavaScript to render their tags?
- It reads the HTML the server returns, without running JavaScript. If your framework injects tags in the browser, they will look missing here. Google can render JavaScript, but server-rendered tags are more reliable for every crawler, including AI crawlers that do not render.
- What is a good title tag length?
- Roughly 30 to 60 characters, or about 600 pixels on desktop. The pixel width matters more than the count: a title full of wide capitals gets cut sooner than one in lowercase.