A meta description is an HTML meta tag placed in a page's head that provides a concise summary of the page's content. While it is not a direct ranking factor, search engines frequently display it as the snippet beneath the page title in search results, making it a key influence on click-through rate. A compelling description acts like ad copy that persuades searchers to choose your result.
The practical length is roughly 150 to 160 characters, because search engines truncate longer descriptions with an ellipsis. Within that space, a good meta description summarizes what the page offers, includes the primary keyword naturally (search engines bold matching query terms), and ideally contains a subtle call to action that sets expectations for what the visitor will find.
When a page lacks a meta description, or has one search engines deem unhelpful, they generate a snippet automatically by pulling text from the page. This auto-generated snippet is often less compelling than a purpose-written one, which is why crafting unique meta descriptions for important pages remains a worthwhile SEO task even though it does not directly move rankings.
Common mistakes include duplicating the same description across many pages, stuffing keywords, exceeding the length limit so the message gets cut off, and writing descriptions that misrepresent the page. Each important page deserves a distinct, accurate description written for humans first. Checking the rendered length before publishing prevents awkward truncation in results.