What does 'IDK' stand for in text messaging?

“What does ‘IDK’ stand for in text messaging?” — “I don’t know.” IDK is a common initialism formed from the first letters of the three words. It is used when someone is uncertain, lacks information, or simply does not want to provide a definite answer.

The abbreviation became especially common in internet chat, texting, forums, and social media, where shortened expressions helped people type quickly. It can appear at the beginning, middle, or end of a sentence: “IDK where she went” or “That movie was, IDK, kind of strange.”

A common mix-up is confusing IDK with “I don’t care.” The two expressions communicate different attitudes: IDK signals uncertainty or lack of knowledge, while “I don’t care” signals indifference. Capitalization is also flexible; “idk” and “IDK” generally mean the same thing. Nearby slang includes IDC (“I don’t care”) and IMO (“in my opinion”).