What Does IDK Mean?

Learning updated on  September 5, 2023 2 min read

IDK is an abbreviation for “I don’t know.”

It’s a common misconception that IDK is part of internet-speak, a set of relatively new abbreviations and lingo we use to talk online or in text messages. Instead, it has been around for much longer. Like many common English abbreviations, it seems to have originated with the US military, in this case during World War I.

Below, you’ll find a more detailed explanation of what IDK means and how to use it.

IDK meaning

IDK means “I don’t know.” You might see IDK in a text message or anywhere else people write notes to each other. It’s typically either an answer to a question or part of a sentence stating you don’t have the information you’re being asked for.

Since its use is casual rather than formal, IDK may be lowercased rather than capitalized. But because it’s an initialism, the capitalized form is the “correct” one.

How to use IDK

You might write IDK when someone asks you a question you don’t know the answer to:

Question: How many peaches do we have on the counter?

Answer: IDK. I’m not at home right now.

Or you might use it when you’re missing information. Any of the following sentences could appear in a text message or email as well as on a chat or social media platform:

  • IDK where that container went.
  • I might be able to pick Sonya up tonight, but idk for sure
  • Tell me which version I have, cause IDK
  • Re: the meeting this afternoon, IDK who’s facilitating.
  • Honestly, idk what she thinks about that idea.
  • If you want to get better at swimming, IDK, maybe take a class?

When to use IDK

As is true for all colloquial abbreviations, using IDK is not a good idea in academic writing. And since it’s less common than some other abbreviations, like FYI or ASAP, some people might not understand you if you use it in work emails. Think carefully about whether the person you’re writing to will know what it means, and if you’re not sure, spell it out.

Formal or informal, your writing can benefit from the insight that AI provides. If your answer to a question about spelling, punctuation, or word choice is “IDK,” QuillBot is the tool to turn to.

What does IDEK mean in texting?

IDEK is an abbreviation that means “I don’t even know.” It’s a stronger statement than simply “I don’t know” (IDK) because it implies that knowing is not possible. However, it can also imply that the missing knowledge is basic and should be known.

What is the meaning of IDK in chat?

IDK means “I don’t know” whether you’re using it in chat, email, text messages, or any other setting.

Is IDK a slang word?

IDK stands for “I don’t know,” which is not slang, but the abbreviation itself could be considered slang. It’s best not to use abbreviations like this one in formal writing.


Hannah Skaggs

Along with Meredith Harris

Hannah, a writer and editor since 2017, specializes in clear and concise academic and business writing. She has mentored countless scholars and companies in writing authoritative and engaging content.

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