How Do I Make Short URLs on Twitter?

With t.co, Twitter automatically shortens URLs to 23 characters

Twitter automatically shortens URLs posted to Twitter, so there's no need to use outside link shorteners like Bitly, unless you're looking for precise data related to the shortened URL.

Twitter and T.co

Twitter limits tweets to fewer than 280 characters. In the past, users relied on link-shortening websites to shorten URLs before posting to Twitter. These ensured that URLs did not take up much space within a tweet. Before long, Twitter introduced its own link shortener—t.co—to minimize character counts.

Twitter URL Shortener Twee.tt
Shekhar_Sahu / Flikr

When you paste a URL into the tweet field in Twitter, it is altered by the t.co service to 23 characters, no matter the length of the original URL. Even if the URL is fewer than 23 characters, it will still count as 23 characters. You cannot opt-out of the t.co link shortening service, because Twitter uses it to gather information about how many times a link is clicked. Twitter also protects users with its t.co service by checking converted links against a list of possibly dangerous websites. When a site appears on the list, users see a warning before they can proceed. 

Using a URL Shortener (Like Bitly) With Twitter

Bitly and a few other URL-shortening websites differ from other link-shortening websites, in that they provide analytics related to the shortened links. When you use the Bitly website, for example, you enter a URL and click the Shorten button to receive a shortened link that is fewer than 23 characters. You can use that link on Twitter, but the t.co service still counts it as 23 characters.

There is no advantage on Twitter to using links shortened by other services. They all register as the same length. The only reason to go to a link-shortener first is to take advantage of the information it keeps on the shortened URL. That information about the number of clicks the shortened link receives, the geographic locations of users who click the link, and any referring websites are still available at Bitly and other similar websites, but you need to set up an account to access it.