Why ‘k’ is the most hated text message, according to science

A study has confirmed what we all suspected: “K” is officially the worst text you can send.

It might look harmless enough, but this single letter has the power to shut down a conversation and leave the recipient spiraling. According to a study published in the International Journal of Mobile Communications, “K” was ranked as the most negatively received response in digital conversations—worse than being left on read or even a passive-aggressive “sure.”

The study found that the single-letter reply often signals emotional distance, passive-aggression, or outright disinterest. Despite its brevity, “K” carries surprising emotional weight. Adding an extra letter—making it “kk”—softens the tone of the reply entirely. Variants like “ok” or “okay,” while still cold, tend to be interpreted as neutral or merely formal.

Many of our day-to-day conversations happen over text, which means there are now unspoken codes of conduct to follow. If you want to open up about your emotions but don’t want to sound too serious, make sure to add “lol” to the end of those texts to show you’re just in a silly, goofy mood, and not suicidal. Giving advice to a friend that you don’t want to be held accountable for? Add an “idk” at the end of the sentence to mitigate culpability.

Nonverbal cues like tone, facial expressions, and body language can be difficult to convey via our phones, leaving the door wide open for misunderstanding and misinterpretation. Sometimes generational differences also impact how we send and interpret texts. In some cases, textual miscommunications can be relationship killers, research has found.

Some texters recognize the power of “k” and are willing to weaponize the letter to serve their own motives. One X user called it “the digital equivalent of slamming the door while making dead eye contact.” Another added: “K is short for ‘you’re dead to me.’ ”

Others advocate for the convenience of the single-letter response: “I’ve learned that rather than replying with a wall of text explaining how you feel, you should just type ‘K’ and hit send. No sense in wasting your valuable words.”

Many suggested other similarly anxiety-inducing replies. “Text her ‘he’s busy.’ see how triggered she gets. lol,” one X user suggested. “No lies told there. … Thumbs up is a very close second for me,” another added.

A third countered: “I raise you ‘we need to talk.’ ”