An "ICYDK" graphic.

ICYDK is a common sight in texts among friends and family members. If you’re unsure what it means, or how to use it in your messages, we’ve got you covered!

What It Means

ICYDK stands for “in case you didn’t know.” It’s used when you’re about to catch someone up on information they likely haven’t heard yet, or to bring up a new topic in a conversation. It can also be used to divulge personal information about yourself to a friend or loved one.

Unlike other initialisms, this one is used less frequently on web forums or social media, or in online comments. Rather, it’s something you’re more likely to see in a text chain or chat with someone you know personally.

For example, your friend might send you a text that says something like, “ICYDK, I switched jobs recently.”

The Origins of ICYDK

Someone typing a text on a smartphone.
Tero Vesalainen/

“In case you didn’t know” has been a common phrase for a very long time. It’s always been used to update others about your life or share news. Some common variations include, “in case you don’t already know,” or, “in case you haven’t heard.”

Like most initialisms, ICYDK started in online chatrooms and forums. It was also used in SMS messaging, which had strict character limits at the time. In 2005, the following definition was posted on Urban Dictionary: “Acronym for ‘in case you didn’t know.'” The poster also noted that ICYDK was often used to keep long-winded posts brief.

ICYDK gained wider usage on social media and chat apps. While it hasn’t been used on the internet as extensively as other acronyms, it’s widely used in texts and personal messages.

JIC (“just in case”) is another acronym that’s used similarly to ICYDK, although it’s less specific. For example, you could say, “I’m sending you this deal JIC you’re interested,” when sending someone a discount they might not know about.

Most People Do Know, Though

When used in personal conversations, ICYDK implies that the other person might already know the info that’s being shared. In this way, ICYDK is a humble way to introduce a major life update.

For example, if someone’s already posted engagement photos on social media, they might send a text like, “ICYDK, John proposed last week,” because there’s a good chance you already know. In this case, the acronym is being used to bring up the subject.

You can also use it to sarcastically joke about how someone seems to be missing a large detail. For example, if a friend tells you someone isn’t replying to them in the middle of the day, you might respond, with, “She has a job, ICYDK.”

However, there are earnest ways to use ICYDK, especially if there’s a strong chance someone hasn’t heard about something yet. For example, if a fellow student missed a class, you might text them something like, “ICYDK, we have a test next week.” Here, you’re sharing information that person probably doesn’t know.


ICYDK also has many similarities with ICYMI (“in case you missed it”). In fact, the two can often be used interchangeably, but there are some key differences that are worth noting.

ICYMI is often used on public posts, whereas ICYDK is normally used in private messages. This is because ICYMI is often used to reference current events or news, whereas ICYDK is more suitable for personal updates. “In case you missed it” also implies that whatever was missed is something worth knowing.

RELATED: What Does "ICYMI" Mean, and How Do You Use It?

How to Use ICYDK

You can use the phrase “in case you didn’t know” in various contexts, including conversations with coworkers or with your family at dinner. The initialism, on the other hand, should most likely be reserved for texts.

Here are a few examples of ICYDK in action:

  • “ICYDK, I’m going to relocate soon.”
  • “The house was painted recently, ICYDK. It might smell weird.”
  • “ICYDK, I’m pregnant!”
  • “There are services that will help you create a website, ICYDK.”

There are many more initialisms you can use to spice up your texts. Be sure to check out HMU and IMY next!

Profile Photo for Vann Vicente Vann Vicente
Vann Vicente has been a technology writer for four years, with a focus on explainers geared towards average consumers. He also works as a digital marketer for a regional e-commerce website. He's invested in internet culture, social media, and how people interact with the web.
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