Telling time is one of the first genuinely useful things you can do in Korean. You need it to catch a KTX train, confirm a café meetup, or answer a stranger on the street in Seoul. But it also happens to be the first place where Korean throws a curveball at English speakers: the language uses two completely different number systems in a single sentence. Hours come from one system, minutes from the other, and mixing them up is the single most recognisable beginner mistake there is.

The good news is that the rule is short, absolute, and never bends. Learn it once and every clock time in Korean falls into place.

The One Rule That Governs Everything

Korean has two sets of numbers:

• Native Korean numbers — 하나, 둘, 셋, 넷… (hana, dul, set, net). Used for counting things, ages, and hours.
• Sino-Korean numbers — 일, 이, 삼, 사… (il, i, sam, sa). Borrowed from Chinese. Used for dates, money, phone numbers, and minutes and seconds.

So the formula for a Korean clock time is:

[Native number] + 시 (si) + [Sino number] + 분 (bun)

Three o’clock twenty is 세 시 이십 분 (se si isip bun). The “3” is native, the “20” is Sino. Both live in the same short phrase. Say 삼 시 and any Korean speaker will immediately know you are a learner; say 세 시 스물 분 and it will sound equally odd in the other direction.

Hours also change shape

Native Korean numbers 1 through 4 (and 20) shorten when they sit in front of a counter word like 시. 하나 becomes 한, 둘 becomes 두, 셋 becomes 세, 넷 becomes 네. This is not optional — it is the only correct form.

The Hours: 1 to 12

A pronunciation note that will make you sound dramatically more natural: 시 tenses to ssi after a consonant-final syllable. 여섯 시 is pronounced [여섣씨], and 몇 시 is pronounced [멷씨] — “myeot-ssi”, never “myeot-si”.

The Minutes: Sino-Korean All the Way

Two shortcuts worth memorising:

• 반 (ban) means “half” and replaces 삼십 분. 세 시 반 = half past three. It is far more common in speech than 삼십 분.
• 전 (jeon) means “before”. 다섯 시 십 분 전 = ten minutes to five. Notice the order is reversed compared with English — the hour comes first, then the minutes, then 전.

Korean has no everyday equivalent of “a quarter past” or “a quarter to”. Just say 십오 분.

Morning, Afternoon and Everything Between

Korea uses the 12-hour clock in daily conversation, so you need a word to mark which half of the day you mean. Crucially, these words go before the time, not after it: 오후 세 시, never 세 시 오후.

새벽 is the one with no clean English equivalent. If a Korean friend says 새벽 두 시에 잤어요, they went to sleep at 2 a.m. — and the word itself carries the “unreasonably late” flavour that “two in the morning” carries in English.

What about the 24-hour clock?

Timetables, boarding passes, TV schedules and the military use the 24-hour clock — and here the rule flips. Written 14:30 is read 십사 시 삼십 분 (sipsa si samsip bun), with Sino-Korean numbers for the hour. This is the one systematic exception, and it belongs to formal announcements, not conversation. In a café you would still say 오후 두 시 반.

Asking for the Time

The core question is short: 몇 시예요? (myeot si-yeyo?) — “What time is it?” Add 지금 (jigeum, “now”) at the front for a fuller sentence.

That last one is the polite way to stop a stranger. Leading with 죄송한데 or 실례합니다 softens the approach the way “excuse me” does in English.

The particle 에

To say “at a time”, attach 에 to the clock time: 일곱 시에 저녁 먹어요 — “I eat dinner at seven.” Attach it once, at the end of the whole time expression: 오후 세 시 십 분에. Note that 에 is not used with 지금, 오늘, 내일, 어제 or 언제 — “내일에 만나요” is wrong; say 내일 만나요.

시 vs 시간: Clock Time vs Duration

This trips up almost everyone. 시 marks a point on the clock; 시간 marks a length of time.

• 두 시 = two o’clock
• 두 시간 = two hours (duration)
• 두 시간 동안 = for two hours

Durations keep the native/Sino split too: hours use native numbers (한 시간, 세 시간), while minutes stay Sino (삼십 분 동안 = for thirty minutes).

Putting It Together

• 7:05 a.m. — 오전 일곱 시 오 분
• 12:30 p.m. — 오후 열두 시 반
• 4:45 p.m. — 오후 네 시 사십오 분 (or 다섯 시 십오 분 전)
• 9:00 p.m. sharp — 밤 아홉 시 정각 (정각 = “on the dot”)
• “The class starts at 10:20.” — 수업은 열 시 이십 분에 시작해요.
• “I work from 9 to 6.” — 아홉 시부터 여섯 시까지 일해요. (부터 = from, 까지 = until)

Four Mistakes to Avoid

1. Sino hours. 삼 시 for 3:00. Always native: 세 시.
2. Unshortened numbers. 하나 시, 둘 시, 열둘 시. Use 한, 두, 열두.
3. Native minutes. 스물 분 for :20. Minutes are always Sino: 이십 분.
4. 오전/오후 in the wrong slot. These come first, like a label on the clock, not after the number.

A quick self-test: cover the tables and say your own daily schedule out loud — when you wake up, when you eat, when you finish work. If every hour comes out native and every minute comes out Sino without you thinking about it, the rule has landed.

Frequently Asked Questions

Why does Korean use two number systems for one clock time?

Korean inherited a full set of Chinese-derived (Sino-Korean) numbers alongside its original native numbers, and over centuries each system settled into different jobs. Native numbers attached to native counter words like 시 (hour) and 살 (years of age); Sino numbers attached to imported measurement words like 분 (minute), 초 (second) and 월 (month). The split feels arbitrary to learners, but it is completely consistent, so it becomes automatic with practice.

Do Koreans actually say 오전 and 오후 in conversation?

Sometimes, but context usually does the work. If you are arranging dinner, everyone knows 일곱 시 means 7 p.m. In casual speech, 아침, 저녁, 밤 and 새벽 are far more common than 오전 and 오후, which sound slightly formal or written. Use 오전/오후 when clarity genuinely matters — booking appointments, confirming flights, or writing messages.

How do I say “half past” and “a quarter to” in Korean?

“Half past” is simply 반 placed after the hour: 여덟 시 반 = 8:30. There is no idiomatic “quarter”, so use the full number — 십오 분 for :15 and 사십오 분 for :45. For “to” or “before”, use 전 after the minutes: 아홉 시 오 분 전 = five to nine.

What is the difference between 시간 and 시?

시 names a point on the clock (“three o’clock” = 세 시), while 시간 measures a span (“three hours” = 세 시간). The same distinction shows up in the question words: 몇 시예요? asks what time it is, whereas 몇 시간 걸려요? asks how long something takes.

Reading a table is one thing; hearing “오후 네 시 사십오 분” at natural speed and answering without hesitating is another. A tutor can drill the number switch with you until it stops feeling like mental arithmetic — book a session with a Korean tutor at The Cognitio and put these phrases to work in a real conversation this week.