Have you ever received a message that said LMK and wondered what it meant? LMK is an initialism that means “let me know.”

Today, we’re taking a closer look at what LMK means, and how and when to use it.

What Does LMK Stand For?

Most acronyms and initialisms have more than one meaning, but these alternate meanings can be quite niche. LMK only has a few alternate meanings in English, and they’re all related to the technology field.

LMK could mean Low Memory Killer in the smartphone business or Local Master Key/Local Maintenance Key to your IT manager. It also occasionally denotes “landmark” on a GPS.

But more often than not, LMK stands for “let me know.” It’s internet slang shorthand and is one of the most widely used abbreviations in direct messaging.

What Does LMK Mean?

LMK is a quick way to ask for additional information in informal communication. Before phones had full keyboards and smart text, the shortened versions of common phrases were useful. Now, they’ve become ubiquitous in electronic communication.

In instant messaging or text messages, LMK means “reply soon.” When someone asks you to let them know in an informal conversation, they usually want your answer in the near future.

Does LMK Have Different Meanings in Text, Snapchat, or Instagram?

LMK has the same meaning across the internet, from message boards to Snapchat. It also means “let me know” in text messages.

It’s common to use LMK in messaging apps because those direct messages are informal communication. You might also see someone on Instagram say, “LMK in the comments,” on their posts as a way to encourage engagement.

Is the Abbreviation/Acronym LMK Slang?

Using LMK to mean “let me know” is slang, and therefore you should avoid using it in any formal communication. This applies to academic and business writing, especially.

But there are also gray areas when it comes to formal and informal communication. Is it okay to message a graduate teaching assistant who’s only a couple of years older than you with LMK? What if you’re talking to a colleague you consider a friend on a work messaging app like Slack or Microsoft Teams?

When in doubt, adopt a more formal tone, and write out the full form of LMK instead.

You can use ProWritingAid to help you with formal communication. Run the Acronyms Report to highlight all of your internet slang like LMK, TBA, WYM, and OFC, so you can replace them with their full forms.

How to Respond to LMK

Even informal conversations have their own norms and expectations. If someone tells you to let them know, it’s best to reply immediately to acknowledge that you will get back to them. Just a simple “OK” or “I will” is enough.

Then etiquette dictates you should get back to them as soon as possible with their requested information. How long that takes will depend on your particular situation.

Examples of LMK Used in Sentences

Now, let’s check out some examples of how you might use LMK in a sentence. Our first example is a conversation between two friends over text message.

Friend 1: hey. are u still going with us to the lake next wknd?

Friend 2: oh man idk. my boss still hasn’t put out the schedule.

Friend 1: ok lmk soon so i can let the campsite know how many ppl are coming

Friend 2: k. i’ll talk to my boss today

You can see that Friend 1 needed specific information for a reason, so he told his friend, “LMK.” Friend 2 immediately acknowledged his request.

Now, let’s look at another example you might see from an influencer on Instagram in a post caption.

Hey, everyone! I just wanted to let all of you know about this amazing new company I’m working with. They make the best gluten-free cupcakes and cookies you've ever had. My friends don’t even believe me when I say they’re gluten-free!

You know you wanna try them. Just use my code INSTAGF for 15% off your first order.

Comment here to LMK what you think of them!

This person used LMK in their call to action (CTA) to get people to engage with their post. You might notice they used an uppercase LMK instead of lowercase like the previous example. There’s no difference, but uppercase acronyms can be easier to read because they stand out more.

There you have it—everything you need to know about the abbreviation LMK. Do you use texting abbreviations in your online chats?

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