What does IDK mean?
A common shorthand for saying that you do not know the answer or are unsure.
Also written: idk · I don't know · I do not know
The meaning
IDK means “I don’t know.” It can be a complete reply or part of a sentence when someone lacks an answer, is uncertain, or has not decided what to do.
What’s the tone?
Informal and concise; it can sound neutral, hesitant, frustrated or dismissive depending on context and how much explanation follows.
When and how to use it
Use it in texts, chats and informal comments just as you would use “I don’t know.” Lowercase idk often feels casual, while all caps can add emphasis; in formal or sensitive conversations, writing the full phrase may sound more attentive.
In a conversation
Original examples to illustrate the expression.
Who changed the meeting link?
IDK—I just opened the calendar and saw the new one.
Do you want noodles or rice?
idk yet; give me a minute to decide.
Easy to misread
IDK means lack of knowledge, not indifference. IDC means “I don’t care,” which is usually more dismissive. In some contexts, IDK may also be a proper name or technical abbreviation, so the surrounding sentence matters.
A little context
IDK is established text and internet shorthand. Oxford identifies it with social media and text messages, while Grammarly documents it as part of text speak and notes written evidence by 2002. This does not claim that year as its first use.
Sources & further reading
These sources support the explanation. The dialogue above is original.
- IDK abbreviationOxford Advanced Learner's Dictionary · Checked Oct 29, 2026
Defines informal IDK as “I don’t know,” identifies its use in social media and text messages, and gives a direct usage example.
- What Does “Idk” Mean?Grammarly · Checked Oct 29, 2026
Explains IDK as the text-speak abbreviation of “I don’t know,” discusses capitalization and informal context, and provides several sentence examples.
- IDK Definition & MeaningDictionary.com · Checked Oct 29, 2026
Defines IDK as “I don’t know” and links the abbreviation to digital communication, with published examples showing contextual use.
Prepared with AI assistance and automated quality checks. Meanings can vary by context. Read our editorial policy.