The two-letter abbreviation commonly used for Instagram is IG. It appears widely in everyday speech, hashtags, captions, marketing, and web addresses connected with the platform.
“IG” is simply an abbreviation of Instagram's name, much like “FB” refers to Facebook and “YT” commonly refers to YouTube. Users may also call Instagram “Insta” or “the Gram,” but IG is the most recognizable two-letter shorthand.
The abbreviation became especially useful as Instagram expanded beyond square photos into video, Stories, messaging, shopping, and short-form clips. Saying that something is “on IG” can therefore refer to many different parts of the service, not just the original photo feed.
A related detail is Instagram's use of the ig.me domain for links to profiles and posts. That reinforces the abbreviation's official visibility, although “IG” remains informal shorthand rather than Instagram's full corporate name.