LMK means “let me know.” People type it at the end of a text when they want something back from you: an answer, an update or your opinion. It is one of the most common shortcuts in texts, DMs and work chats, and it has a place in our Gen Z slang list too. The real skill is not decoding the letters but working out what the sender is waiting for.
What does LMK mean in a text?
In a text, LMK hands the next move to you. The sender has shared a plan, a question or a piece of news, and now they are waiting on your side of it. Sometimes they need a quick yes or no, and sometimes they only want to hear from you later. The table below shows the five jobs LMK usually does and a reply that fits each one.
| What they want | Example text | A reply that works |
|---|---|---|
| A yes or no | “Pizza at mine Friday? lmk” | “Yes, count me in!” |
| A choice | “Red or blue for the logo? lmk” | “Blue, it’s easier to read.” |
| An update later | “lmk when you land” | “Will do. Boarding now.” |
| Your opinion | “Just sent my essay, lmk what you think” | “Reading it now, I’ll send notes tonight.” |
| A heads-up if plans change | “I’ll be there at 7, lmk if anything changes” | “Sounds good, see you then.” |
Look for a time word next to it, like “tonight” or “by Friday.” A deadline means the sender needs to plan around your answer, for example to book a table or buy tickets. When there is no deadline, the request is softer and a reply later in the day is fine. LMK also often sits next to a question, such as “wyd later? lmk,” where the wyd question is the real ask and LMK just invites the answer.
Is LMK rude or passive-aggressive?
LMK is friendly in almost every case. It is short because texting is quick, not because the sender is cold. Still, small details can change how it lands, the same way a full stop can make “ok.” sound flat. The tone table below shows how the same three letters can read.
| How it is written | How it usually reads |
|---|---|
| lmk! | Warm and upbeat |
| lmk | Neutral, the normal way |
| lmk. | A little flat, or all business |
| LMK ASAP | Urgent, they need it now |
| lmk?? (after no reply) | A second nudge, they are still waiting |
If you get a second “lmk??,” it usually means your first silence felt longer to them than to you. A quick “Sorry, just saw this!” fixes most of that. If you are the one sending it, adding a reason helps a lot. “lmk by 5 so I can order” sounds kind, while a bare “LMK” after a long wait can feel like a push.
How do you reply to LMK?
Answer the thing they asked about, not the letters. If you know the answer, give it in the first few words. If you do not know yet, say when you will know, because that is what LMK is really asking for. A short “Not sure yet, I’ll tell you by tonight” is better than leaving the message on read.
- To say yes: “I’m in!” or “Yes, works for me.”
- To say no kindly: “Can’t make it this time, but thanks for asking.”
- To buy time: “Let me check and I’ll get back to you by 6.”
- To ask for more: “What time were you thinking?”
- To promise an update: “Will do” or “lyk when I’m home.”
LMK vs LYK: which one do you send?
The two are mirror images. LMK asks the other person to tell you something, while LYK means “let you know” and promises that you will tell them. So if a friend writes “lmk if you can come,” a natural reply is “I’ll lyk tomorrow.” We explain the reply side in our LYK guide.
What do lmkwyt, lmk asap and other add-ons mean?
People bolt extra letters onto LMK to say exactly what they want to know. A common one is lmkwyt, short for “let me know what you think.” Its Urban Dictionary entry is dated 16 October 2009, so the add-ons are not new. Here are the ones you are most likely to see.
| Version | Stands for | When people use it |
|---|---|---|
| lmkwyt | Let me know what you think | After sharing a photo, a draft, a song or an idea |
| lmkyt | Let me know your thoughts | The same ask, a little more polite |
| lmkwyk | Let me know when you know | When you are waiting on news from someone else |
| lmk asap | Let me know as soon as possible | When there is a deadline |
| lmk if you need anything | Let me know if you need anything | An offer of help, not a question |
Notice that the last one is different from the rest. “Lmk if you need anything” does not ask for a reply at all, so “Thanks, I will!” is enough. The others expect an answer, even a short one. If you get a long string of letters that is not on this list, paste it into our text slang translator to check it.
Can you use LMK at work?
In a quick chat with coworkers you know, LMK is normal. Merriam-Webster lists it with other everyday texting shortcuts, and it fits fine in Slack or Teams messages between teammates. In an email to a client, a manager you have just met or anyone outside your company, write “let me know” in full. It costs you eight extra letters and avoids looking rushed.
Where did LMK come from?
Nobody has pinned down who first wrote LMK. Many sites say it began in 1990s chat rooms, but none of the pages we checked gives a dated example to prove it. The oldest Urban Dictionary entry we found for it is dated 30 September 2003, and it already defines LMK as “let me know.” Dictionary.com now lists it as an acronym for the same phrase and shows posts from 2017 and 2018 that use it to ask for feedback.
Does LMK ever mean something else?
Yes, a few times, but context makes it easy to tell. In a normal text it is “let me know” almost every time. The other meanings are names of things, plus some joke and adult readings on Urban Dictionary that you will not meet in everyday chat. Here are the ones worth knowing.
| LMK as… | What it is | How to tell |
|---|---|---|
| An app | An anonymous polls app that works with Snapchat | It shows up as an app name or a poll link, not inside a sentence |
| A song | “LMK” by Kelela, released on 1 August 2017 on Warp Records | Song lists, playlists and music posts |
| A joke reading | Made-up expansions on Urban Dictionary | Only when someone is clearly joking |
What should parents and teachers know about LMK?
If a child or student writes “lmk,” they are almost always asking for an answer, and there is nothing hidden in it. The one thing worth a closer look is the LMK app. Common Sense Media rates it for ages 17 and up and sums it up as anonymous Snapchat polls that invite compliments and trouble. In May 2021, Engadget reported that Snap suspended LMK’s link to Snapchat while it looked into a lawsuit about bullying through anonymous apps.
So the term itself is safe, and the app is a separate question. If you see LMK as an app name on a young person’s phone, ask what they use it for and who can send them messages. Anonymous polls can be fun, but they make it easy for unkind messages to arrive with no name attached. A calm talk usually works better than a ban.
Can you read these LMK texts?
Try these four quick questions to check what you have learned. Each one is a real kind of message you might get. Tap an answer to see if you are right and why. If scripts are off, the reasons show under each question.
1. “Sent you the poster design, lmkwyt” — what do they want?
Your opinion on the design. Lmkwyt means “let me know what you think,” so they want feedback.
2. “lmk by 5 so I can book the table” — what is the best reply?
“Yes, book it for me too!” before 5 is best. The time next to LMK is a deadline, and they need your answer to plan.
3. A friend says “lmk if you can come.” Which reply promises to tell them later?
“I’ll lyk tomorrow” is the right one. LYK means “let you know,” the reply side of LMK.
4. True or false: LMK is too rude to use in any work chat.
False. LMK is normal in quick chats with coworkers you know, but write “let me know” in emails to clients or new contacts.
Last checked: October 12, 2026
