합니다 vs 해요 — the two polite Koreans, and why subtitles merge them

Short version: polite Korean has two main styles. The formal one ends in –ㅂ니다 / –습니다 and sounds crisp, official, a little stiff. The everyday polite one ends in –요 and sounds warm and respectful. Both are polite. Characters move between them constantly, and English has no way to show it.

합니다 · 해요 hamnida · haeyo — explained in four panels

What the subtitle saysI understand.

What was actually said알겠습니다 — ‘Understood.’ (Formal, like reporting to a superior.)

The two styles

	Formal (합쇼체)	Polite (해요체)
It’s okay	괜찮습니다	괜찮아요
I understand	알겠습니다	알겠어요
Thank you	감사합니다	고마워요
Where is it?	어디입니까?	어디예요?
Feel	Official, public, crisp	Friendly, respectful, soft

Where you hear the formal style

News anchors and announcements
Presentations, speeches, meetings
Military service — so strongly that it has a nickname, 다나까, after the endings –다, –나, –까
Staff greeting customers: 어서 오십시오, 감사합니다
First meetings, especially in business
Newer employees speaking to senior managers

The polite –요 style is everything else: most shopping, most conversations with people older than you, most of daily life. A reasonable rule is that –요 is the default and –습니다 is for when the situation is official or you want to show extra deference.

Where this comes from

Korean grammar marks the relationship between speaker and listener in the verb ending, a system known as speech levels. Traditional grammars list more than two polite levels, some of which now sound archaic or appear mainly in historical dramas. In modern everyday speech, the two polite ones above do most of the work, alongside 반말, the casual style.

What a switch tells you

Most people mix both styles, even within one conversation — formal to open and close, –요 in the middle. That is normal. But a sudden switch means something:

From –요 to –습니다: cooling off, getting formal, “let’s keep this professional.”
From –습니다 to –요: warming up, relaxing, becoming more personal.
A young man speaking in 다나까 style: he’s probably just finished military service, and his friends will tease him for it.

Men and women both use both styles. Older descriptions sometimes claimed men prefer –습니다 and women prefer –요. Any such tendency is weak and depends far more on job and situation than on gender.

What subtitles do

They can’t do much. 알겠습니다 and 알겠어요 both become “I understand” or “Got it.” Occasionally a translator adds “sir” or “ma’am” to hint at the formal style, but that adds a word that wasn’t there. The result is that a character’s whole shift in tone — a subordinate dropping into stiff formality because they are angry, or a couple’s first softening into –요 — goes past unseen.