What search engines and social platforms actually read
Meta tags are HTML elements in a page’s head that describe the page to machines: the title and description a search engine may display, the canonical URL that identifies the preferred version, and the Open Graph and Twitter Card properties that build link previews.
There is a persistent myth that meta tags are an SEO lever. Most are not. The keywords meta tag has been ignored for well over a decade, and the description tag is not a ranking factor. What these tags actually control is presentation — how your page is described in a result and what a link looks like when somebody pastes it into Slack, LinkedIn or WhatsApp.
Presentation is worth taking seriously because it decides click-through. This page covers the length limits that matter, why Google rewrites descriptions, how canonical tags are treated, and the Open Graph properties that are genuinely required.
Length guidance, and why it is approximate
Direct answer: Google truncates on rendered pixel width, not character count. Character targets are a proxy — a title of 60 narrow characters may fit where 55 wide ones do not.
- Title tag
- Aim for roughly 30–60 characters. This tool warns below 30 (you are leaving space unused) and above 60 (likely truncation). Put the distinguishing words first; brand names belong at the end.
- Meta description
- Aim for roughly 120–160 characters. The tool warns below 120 and above 165. Front-load the useful part, since the tail is what gets cut.
- Canonical URL
- An absolute URL including the protocol. Relative canonicals are technically valid but a frequent source of errors on staging domains.
- Open Graph image
- 1200 × 630 pixels is the near-universal recommendation, giving a 1.91:1 ratio. Keep it under a few hundred kilobytes so previews render before the reader scrolls past.
- Twitter Card
- summary_large_image is the useful default. Where a Twitter-specific tag is missing, the platform falls back to the matching Open Graph property — so you rarely need to duplicate everything.
- The keywords tag
- Ignored by Google since 2009. Including it does no harm and no good; the only thing it reliably does is show competitors your target terms.
Weak tags and stronger rewrites
The pattern to aim for: specific subject first, differentiator second, brand last — written for a person deciding whether to click.
Example 1: A title that wastes its best characters
Home | Acme Digital Solutions Ltd — Official WebsiteShopify Migration Services for UK Retailers | AcmeThe first version says nothing a searcher was looking for. The second names the service, the market and the brand in 51 characters.
Example 2: A description that repeats the title
We are a leading provider of digital solutions. Contact us today to learn more about our services and solutions.Move your store from Magento to Shopify without losing rankings. Fixed-price migration, 301 redirect mapping and a two-week rollback window.The rewrite is 143 characters, contains three concrete facts, and gives a reason to click. Vague superlatives are exactly the text Google replaces with a page excerpt.
Example 3: A share card with no image tag
<meta property="og:title" content="Our new report">
(no og:image)<meta property="og:title" content="2026 UK Ecommerce Migration Report">
<meta property="og:description" content="…">
<meta property="og:image" content="https://example.com/og/report.png">
<meta property="og:url" content="https://example.com/report">Without og:image, platforms either guess an image from the page or show a bare text link. A deliberate 1200 × 630 card measurably improves engagement — build it with the image resizer.
Where meta tags behave differently than expected
Google rewrites descriptions, and that is normal
When a passage in the page body answers the query better than your description, Google shows that passage instead. It happens on a large share of results. Write a good description for the queries you care most about and accept substitution elsewhere.
Canonical is a hint, not an instruction
Search engines weigh canonical tags alongside internal links, sitemaps and redirects. Contradictory signals — a canonical pointing one way while links and the sitemap point another — get resolved by the search engine, not by you.
Social platforms cache previews aggressively
Fixing an og:image will not change a link that has already been shared until the platform re-fetches it. Use each platform’s debugging tool to force a refresh.
Duplicate titles across pages
Templated titles such as "Products | Brand" on two hundred pages give search engines nothing to distinguish them. Every indexable page deserves a title only it could have.
A noindex tag on a blocked page does nothing
If robots.txt prevents crawling, the tag is never read. Check crawl rules with the robots.txt generator and tester before assuming a page will drop out.
Emoji and special characters are unpredictable
They sometimes render in results and sometimes get stripped. Never let the meaning of a title depend on one.
A per-page meta audit
- One unique title per indexable page, with the distinguishing terms in the first 40 characters.
- A description that adds information rather than repeating the title.
- A self-referencing absolute canonical on every page, pointing at the version you want indexed.
- og:title, og:description, og:image and og:url present, with the image at 1200 × 630.
- twitter:card set to summary_large_image; let the rest fall back to Open Graph.
- A preview check for every important page before publishing, and a length check against the word counter when a description is close to the limit.
How this page is maintained
The length thresholds shown here match the warnings this generator produces (under 30 and over 60 for titles; under 120 and over 165 for descriptions). Statements about Google rewriting descriptions, canonical tags being hints, and the keywords tag being ignored reflect the search engines’ own published guidance.
Written and reviewed by the ToolsRacks editorial team. Last reviewed: .