# How to Use LMK Correctly: Tech English Mistakes (2026)

> LMK stands for "let me know".

- **Term:** LMK
- **Part of speech:** abbreviation
- **Pronunciation:** /ˌɛl ɛm ˈkeɪ/
- **English level (CEFR):** A2–B1
- **Register:** Casual, Written
- **Region:** US and UK
- **Topic:** [Meeting phrases](https://app.speaktechenglish.com/learn/topics/meeting-phrases.md)
- **Lesson:** https://app.speaktechenglish.com/learn/lmk
- **Last updated:** 2026-10-29

## Meaning

LMK stands for "let me know". It asks someone to tell you something, like a decision, an answer or whether they need help.

LMK is a friendly way to end a Slack message: "LMK if you have questions" or "LMK what you think." It is softer than a direct request, because it leaves the timing up to the reader. If you need a reply by a certain time, add it: "LMK by Thursday." In email to clients or senior people, write "Please let me know."

## When you hear it

You share a draft with a teammate and want them to tell you if anything is wrong.

## Examples

- **in Slack:** "Shared the draft in the doc. LMK if anything looks off."
- **offering help:** "I've used that library before, LMK if you get stuck."
- **asking for a decision:** "Can you LMK by EOD whether we're going with option A or B?"

## What native speakers say

- "LMK if you have any questions."
- "LMK what you think."
- "LMK by Thursday so I can book the room."

## Common mistakes

- ✗ "Please LMK me." → ✓ "Please let me know. / LMK." ("Me" is already in LMK.)
- ✗ "LMK. (when you need an answer by noon)" → ✓ "LMK by noon, please, so I can send it to the client." (LMK has no deadline. Add one if timing matters.)
- ✗ "LMK (in an email to a new client)" → ✓ "Please let me know if you have any questions." (LMK is casual chat shorthand. Write it out for clients.)

## Be careful

LMK is casual. Use "Please let me know" with clients, senior leaders or in formal email.

## Word forms

| Part of speech | Word | Example |
| --- | --- | --- |
| full form | let me know | Let me know if you need anything. |
| with if/what/when | LMK if / what / when | LMK when you're free. |


## Collocations

- **LMK if**: offer help or invite questions
- **LMK what you think**: ask for feedback
- **LMK by**: add a deadline

## Synonyms

- **let me know**: neutral, works everywhere
- **keep me posted**: ask for updates over time
- **shout if**: very casual, UK

## Opposites

- no reply needed
- FYI only

## Practice

This lesson has 4 practice exercises with instant feedback on the page: https://app.speaktechenglish.com/learn/lmk

## FAQ

### What is the full form of LMK?

LMK stands for "let me know".

### Is LMK rude?

No. It is friendly and casual. Just write "let me know" in formal email.

### How do I add a deadline to LMK?

Add "by" and a time: "LMK by Friday".

### What is the difference between LMK and keep me posted?

LMK asks for one answer. Keep me posted asks for updates over time.


## Related

- [ping](https://app.speaktechenglish.com/learn/ping.md)
- [loop in](https://app.speaktechenglish.com/learn/loop-in.md)
- [heads-up](https://app.speaktechenglish.com/learn/heads-up.md)
- Full glossary: https://app.speaktechenglish.com/learn.md
- Live lessons with a coach: https://app.mocklyenglish.com

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