Slang meaning

What does LMK mean?

LMK is how people type “let me know” when they want an answer but aren't in a rush: “lmk if you want to come.” It can ask for a decision, an update or a favour, and its tone runs from warm and open to quietly impatient.

Updated 6 October 2026

It means “let me know”: a casual request for a reply, a decision or an update once the other person has one.

Stands for: Let me knowTone: casual and open; can turn impatient

What LMK can mean

1. Tell me when you know

The everyday sense. LMK hands someone a question and lets them answer in their own time: “lmk when you land,” “lmk what size you need.” It expects them to come back to you, so it suits plans, orders and favours. It usually sits at the end of a message, in lower case.

2. A soft, open offer

“Lmk if you need anything” offers help without pushing it. After a breakup, a loss or a house move, it's a kind line, but it leaves the asking to the other person, and not everyone will ask. A specific offer, like “I can bring dinner on Thursday,” is often easier to say yes to.

3. A pointed nudge

Sent after a silence, LMK can carry an edge. “Lmk if you're still coming” two hours after the plan, or “lmk when you decide to reply,” is polite on the surface and impatient underneath. A full stop or capital letters make it sharper: “LMK.” reads like a raised eyebrow.

How people use it on Instagram and Facebook

  • Plans in DMs and group chats

    Most LMKs are logistics: who's in for Saturday, what time the train gets in, whether to add someone to the cinema booking. In a busy group chat, “lmk by 6” sets a soft deadline without sounding bossy.

  • Stories with a question sticker

    Creators pair “lmk” with Instagram's question sticker to collect answers: “lmk your favourite café in town,” “lmk what to bake next.” Answers arrive privately, and the account can share the best ones back to its Story.

  • Marketplace and shop chats

    Sellers on Facebook Marketplace and small Instagram shops often end with “lmk if you have any questions.” It's friendly, but it gives the buyer nothing specific to answer. A concrete question, such as “delivery or collection?”, keeps the chat moving.

  • Captions that ask for opinions

    “Lmk in the comments” closes plenty of captions: “green or blue? lmk below.” A quick either-or choice like that is easy to answer, while a vague “thoughts? lmk” gives followers much less to go on.

LMK in real conversations

  • Direct message
    booking the table for 8, lmk if you're in by tonightin! put me down for two
  • Story reply
    need podcast recs for a long drive, lmk 🎧anything about unsolved mysteries, you won't notice the miles
  • Facebook comment
    Yes, still available. Collection only, near the station. Lmk a time that suits.Could I come by on Thursday after 5?
  • Text message
    lmk when you get home safehome ❤️
  • Instagram comment
    do you ship to Pune? lmkWe do. Sending you a DM with delivery times now.

How to reply to LMK

Questions people ask

What does “lmk wyd” mean?

“Let me know what you're doing.” It's usually the start of making plans, as in “lmk wyd later, might get food,” rather than someone checking up on you. A quick line about your plans is all it needs.

Do I have to answer an LMK straight away?

No. The whole point of LMK is that you answer when you know. If you need time, a holding reply such as “I'll know by Friday” stops the other person wondering, and it's kinder than going quiet.

Why does “lmk.” with a full stop sound annoyed?

Because casual texts usually skip the final full stop, so adding one can feel clipped. “lmk.” after a long silence sounds like “I've been waiting,” while “lmk 😊” keeps it easygoing. Same letters, different mood.

Is “lmk if you have any questions” a good line for a shop?

It's polite, but it puts the work on the customer. Ask one specific thing instead, such as their size, the date they need it by or where it should be delivered. A clear question is easier to answer and moves the order along.

Is LMK fine in work messages?

With colleagues in a chat app, yes; it's everywhere. In an email to a client or a manager you don't know well, “please let me know” reads better and costs only a few more letters.

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