LMK is one of the most useful texting acronyms. It stands for let me know and asks someone to share information, give an answer or update you. You will see it in group chats, work messages, social media and dating apps. This guide explains what LMK means, how to use it, how to reply and when to use the full phrase instead.
What does LMK mean?
LMK = Let Me Know. It politely asks someone to tell you something.
| Example | Meaning |
|---|---|
| Lmk if you want to come | Tell me if you want to join |
| Lmk when you get home | Text me when you arrive home |
| Lmk what you think | Share your opinion |
| Lmk asap | Tell me as soon as possible |
| Lmk by Friday | Give me an answer by Friday |
| Lmk if you need anything | Tell me if you need help |
Where did LMK come from?
Let me know is a common English phrase. The acronym LMK became popular with early texting and instant messaging in the 2000s, when people shortened phrases to save time and characters. It remains widely used across generations.
How to use LMK
Making plans
- Dinner at 7? Lmk.
Asking for opinions
- Lmk what you think of the design.
Safety check-ins
- Lmk when you get home safe.
Offering help
- Lmk if you need a ride.
Work chats
- Lmk if you have questions about the report.
Frequently asked questions
Is LMK professional?
It is fine in casual workplace chats, but write let me know in formal emails.
How do I reply to LMK?
Answer the question, or say will do, I will let you know.
Example conversations using LMK
Example 1: Plans
Leo: Going to the beach Saturday, lmk if you want to come. Mia: I am in! What time?
Example 2: Safety
Mom: Drive safe, lmk when you get there. Teen: Will do. (Later) Teen: Here!
Example 3: Work
Manager: Draft is in the shared folder, lmk your feedback by Thursday. You: Got it, will review today.
Example 4: Shopping
Ana: I can pick up groceries, lmk what you need. Zoe: Milk, eggs and bread, thanks!
Example 5: Dating
Raj: I would love to take you to dinner this weekend, lmk if you are free. Kim: Saturday works!
How to reply to LMK
| Situation | Reply |
|---|---|
| You know the answer | Yes, I will be there at 7 |
| You need time | Let me check and get back to you |
| You will update later | Will do |
| You are not interested | Thanks, but I cannot make it |
| You need more details | Sure, what time are you thinking? |
Replying even briefly is polite, because LMK means someone is waiting for your answer.
LMK and related acronyms
| Acronym | Meaning |
|---|---|
| LMK | Let me know |
| HMU | Hit me up |
| WYD | What you doing |
| TTYL | Talk to you later |
| NVM | Never mind |
| IDK | I do not know |
| IDC | I do not care |
| ASAP | As soon as possible |
| EOD | End of day |
| FYI | For your information |
See our guides on what HMU means and what WYD means for related phrases.
LMK at work
LMK is common in workplace chat tools like Slack and Teams. It is usually fine with colleagues, but in emails to clients, executives or people you have not worked with before, writing please let me know looks more polished.
| Casual (chat) | Professional (email) |
|---|---|
| Lmk if you have questions | Please let me know if you have any questions |
| Lmk asap | Please let me know at your earliest convenience |
| Lmk by EOD | Could you please let me know by the end of the day? |
Making LMK more effective
LMK is open-ended, so people sometimes forget to reply. To get faster answers:
- Add a deadline: Lmk by 5 p.m. so I can book the table.
- Be specific: Lmk if Saturday or Sunday works better.
- Offer options: Pizza or tacos? Lmk.
- Explain why: Lmk by tonight, tickets sell out tomorrow.
Clear questions lead to clear answers.
LMK in different contexts
| Context | Example | Purpose |
|---|---|---|
| Friends | Lmk if you want to carpool | Coordinating plans |
| Family | Lmk when you land | Safety check-in |
| School | Lmk if you finished your part of the project | Group work update |
| Work | Lmk if the numbers look right | Request feedback |
| Selling online | Lmk if you are interested | Inviting buyers |
| Dating | Lmk if you want to grab coffee | Invitation |
Quick facts about LMK
- Stands for: Let Me Know
- Meaning: please tell me or update me
- Tone: casual, polite
- Popular since: early texting in the 2000s
- Professional alternative: please let me know
- Related: HMU, TTYL, ASAP, EOD
Parents’ guide to LMK
LMK is a harmless and useful acronym. Parents often use it themselves, like lmk when you get to school. It is a great tool for safety check-ins with teens. Agreeing on a habit, such as always texting when you arrive somewhere, builds trust and peace of mind.
Captions with LMK
- New recipe on my page, lmk if you try it.
- Planning a trip to Bali, lmk your must-see spots.
- Starting a book club, lmk if you want in.
- Lmk your favorite coffee shops in town.
- New playlist dropped, lmk what you think.
- Selling my old camera, lmk if interested.
Variations of LMK
- lmk (lowercase, most common)
- LMK (uppercase, emphasis)
- lmkk (friendly, casual)
- lmk asap (urgent)
- lmk tho (casual reminder)
- pls lmk (polite request)
- let me know (full phrase, professional)
Why LMK is so useful
LMK is short, polite and versatile. It works for planning, safety, feedback, sales and invitations, and it is understood by nearly everyone who texts. Unlike trendier slang, LMK does not sound dated or confusing, which is why parents, coworkers and teens all use it comfortably. It keeps conversations moving without demanding an immediate reply.
Common LMK mistakes
- No deadline: Without a time frame, people may forget to respond.
- Vague questions: Lmk about the thing does not help the other person.
- Using it in formal emails: It can look too casual for clients or senior leaders.
- Overusing it: Ending every message with lmk can feel like you are pushing for replies.
- Not following up: If someone does not answer, a friendly reminder is fine.
LMK vs keep me posted
| Phrase | Meaning | Use |
|---|---|---|
| LMK | Tell me an answer or update | One-time answer or decision |
| Keep me posted | Update me over time | Ongoing situations |
| Keep me in the loop | Include me in updates | Work and group projects |
| Get back to me | Reply later with an answer | Follow-up requests |
How to follow up after LMK
If someone has not replied:
- Wait a reasonable time based on urgency
- Send a friendly nudge: Hey, just checking in on this
- Restate the question clearly
- Offer a simple choice or deadline
Polite follow-ups keep plans on track without pressure.
LMK on dating apps
On dating apps, LMK is a low-pressure way to invite someone to plan a date: I know a great taco spot, lmk if you are free Thursday. It gives the other person space to respond and shows clear intentions. Pairing LMK with a specific idea and time makes it easy for them to say yes.
LMK around the world
LMK is used in English-speaking countries everywhere and is widely recognized by non-native speakers online. Many languages have their own short versions, like the Spanish avÃsame (let me know) or the Malay bagitahu, but LMK remains a common choice in international group chats and business messaging.
Final thoughts
LMK means let me know. It is one of the most practical and polite texting acronyms, perfect for making plans, asking for feedback, offering help and checking in on loved ones. Use it casually with friends and coworkers, add a deadline when you need a quick answer, and switch to please let me know in formal emails. It is a small phrase that keeps communication flowing smoothly, and it is likely to stay in everyday use for years to come. For a complete list of texting slang, start with our guides to what SMH means, what TBH means and what NGL means.
LMK message templates
Copy and adapt these quick templates for everyday situations:
| Situation | Template |
|---|---|
| Group dinner | Booking a table for Friday at 7, lmk by Wednesday if you are in |
| Ride share | Heading to the airport at 6 a.m., lmk if you want a lift |
| Project feedback | Shared the draft in the folder, lmk any edits by Monday |
| Party invite | Birthday picnic Sunday at noon, lmk if you can make it |
| Safety | Have fun tonight, lmk when you are home |
| Selling an item | Bike is still available, lmk if you want to see it |
Each template includes the key details and a clear time frame, which makes it easy for people to reply quickly.
Keep these handy, and you will never have to wonder how to phrase a quick request again. A clear lmk saves time for everyone.
The bottom line
LMK means let me know. It is a quick, polite way to ask for information or an answer. For more texting slang, see what HMU means and what WYD means.