Where it sits
Lmk sits in the middle: casual enough for friends, neutral enough for most work chats.
Tell it apart
| Aspect | Lmk | Hmu |
|---|---|---|
| Stands for | Let me know | Hit me up |
| Asks for | An answer or update | Contact |
| Register | Neutral, fine at work | Casual |
Lmk asks for a specific piece of information later. Hmu asks someone to get in touch, about anything.
What it really means
Lmk is the politest deadline you can send. It stands for "let me know", and it asks for an answer while leaving the timing to the other person.
That's the whole of its charm. "Lmk what you want" means take your time looking at the menu. "Lmk when you land" means I'll be thinking about you, but I won't keep checking. "Just lmk by Friday" adds a limit but keeps it light. Few abbreviations work as well in a family group chat and in a work channel.
Its history is short and not well documented. How-To Geek dates the earliest available Urban Dictionary definition to 2003. Dictionary.com lists the abbreviation but gives no date, and we found no earlier record, so that's where its story starts for now.
It's often confused with hmu ("hit me up"), and the two overlap. The difference is in what you're asking for. Hmu asks someone to get in touch. Lmk asks for something specific: a time, a choice, a yes or no. When you don't know yet, the natural reply joins it to idk: "idk yet, I'll lmk."
Where it comes from
let
me
know
A request that leaves the timing to the other person, which is what makes it polite.
- 2003
Earliest available Urban Dictionary definition, according to How-To Geek.
In real life
- Text: "we're ordering pizza, lmk what you want"
- Text: "lmk when you land"
- Text: "no rush, just lmk by Friday if you can make it"
Questions
Q01What does lmk mean in a text?
"Let me know." It asks the other person to tell you something when they can: "lmk if you're coming" or "lmk when you land".
Q02How should I reply to lmk?
With the information, when you have it. If you don't know yet, "will do" or "I'll lmk tonight" tells them you've seen the request.
Q03Is lmk OK at work?
In most informal work chats, yes. In a formal email, "let me know" written out is safer.
Q04How old is lmk?
How-To Geek dates its earliest available Urban Dictionary definition to 2003. No dictionary we checked gives an earlier date.