Meta Description Character Limits

The Meta description is a series of Meta tags that contain information about a Web page and is placed in the "header" section of the Web page code. Here, they are invisible to the page visitor but are visible to search engines. The Meta tag is optional but will help your page rank for keywords found in the text of the description. It will also help a searcher understand what your page is about. But sometimes your description text will not show up in the search results entry for your page.

How the Meta Description Tag Works
Search engine results list the page title in bold type, followed by two lines of text that tell something about the page. In theory, these two lines of text should be the text contained in your Meta Description tag for the page. Therefore, since this section of the search results entry has a maximum length (which is slightly different for each search engine), you should set a maximum length for the text in your Meta Description tag so all the text you enter shows up on the search engine results.

Why Your Meta Description Might Not Match the Search Engine Description
In the real world of Web search, the text from a page's Meta Description tag is not always the text that shows up on the search results page. If the searcher searches for a keyword phrase that is not part of the description, the text will often be part or all of the sentence from the page containing the keyword phrase, rather than the Meta Description. So if you have a page about hot air balloons that happens to also contain your full name, and if someone searches for your name as a search term, the results will show the sentence from the page containing your name instead of the description.

Limit for Various Search Engines
Different search engines have a different maximum length for the various parts of their search result entries. SEO experts recommend you pick the smallest limit and use that, so that no matter which search engine someone uses, they will see the entire description if the search engine includes it. The character limit for Google is 156, for Yahoo it is 161, for Bing it is 150 and for Ask.com it is 312 characters, though they seem to display text from the page rather than the description. Therefore, your best bet is to write a Meta Description tag with text that is no longer than 150 characters.

Considerations
When planning what to write in the Meta Description, don't just consider character count. Think of this text like a mini ad for your page. It should tell what's on the page but in a compelling way so the person reading it is interested and wants to click on your link rather than the next one.