Half, To, and Past: 반, 전, 후

Once you can say a bare time — [native hour] 시, [Sino minute] 분 — the next step is to speak about time the way people actually do: half past two, ten to three, in thirty minutes, at five o'clock sharp. Korean handles all of these with a small set of relational words that attach to a clock time: 반 (half), 전 (before/to), 후 (after), and 정각 (exactly, on the dot). The words themselves are easy. The trap is word order — Korean builds 전 clauses in the opposite sequence from English, and if you calque the English order the sentence comes out backwards.

반: half past

반 literally means "half," and it stands in for 삼십 분 (30 minutes). 두 시 반 is "two-o'clock half" = 2:30. It attaches directly after the hour, with no counter and no particle in between.

반 and 삼십 분 mean exactly the same clock position and are freely interchangeable — but in everyday speech, 반 is far more common than 삼십 분. Saying 삼십 분 for 2:30 is not wrong; it just sounds a touch more precise or formal, the way an English speaker who says "fourteen thirty" instead of "half two" sounds slightly official.

전: before / to — and the word-order trap

전 means "before," and with clock times it does the job of English "to" (as in "ten to three"). Here is the critical point: 전 is a postposition — it comes after the amount of time it refers to — and the whole expression assembles in Korean order:

[target hour] 시 · [minutes] 분 · 전

So "ten to three" is not built as "ten-before three." It is built as 세 시 십 분 전 — literally "three o'clock, ten minutes before." You name the hour you are counting down to first, then the gap, then 전.

Read 아홉 시 오 분 전 slowly: "nine o'clock — five minutes — before." Every piece is in the reverse order from the English "five to nine," and that reversal is the whole difficulty. English front-loads the gap ("five to"); Korean front-loads the destination hour (아홉 시) and leaves 전 for last. If you translate the English string word by word, you produce ×오 분 전 아홉 시, which no Korean would say.

후: after — mostly for durations

후 means "after" and is the mirror of 전. In practice, Korean uses 후 far more for durations ("in thirty minutes," "an hour later") than for reading a clock face. You will rarely hear 후 used to say a specific o'clock time; instead it counts forward from now.

Note that 시간 ("hour" as a duration) is different from 시 ("o'clock" as a point). 한 시 is "one o'clock"; 한 시간 is "one hour long." Both use the native number 한, but the counters differ, and 후 typically pairs with the duration counter 시간, not the clock counter 시. The particle 에 follows 후 to place the event: 삼십 분 후에.

정각: on the dot

정각 means "exactly / on the dot" and follows the hour to stress that there are no stray minutes: 다섯 시 정각 = "five o'clock sharp." It is common in announcements, appointments, and anywhere punctuality is the point.

Common Mistakes

1. Calquing English word order into 전. This is the signature error. English "five to three" fronts the gap; Korean fronts the destination hour and ends with 전.

• ✗ 오 분 전 세 시
• ✓ 세 시 오 분 전 — se si o bun jeon — "five to three"

2. Pairing 반 with a number. 반 already is the half; it takes no minute number in front of it.

• ✗ 두 시 삼십 반 / 두 시 반 삼십 분
• ✓ 두 시 반 — du si ban — "half past two"

3. Using the wrong number system in a 전/후 phrase. The minutes inside a 전/후 expression are still ordinary clock minutes, so they stay Sino: 오 분 전, not ×다섯 분 전.

• ✗ 다섯 분 전
• ✓ 오 분 전 — o bun jeon — "five minutes before / five to"

4. Confusing 시 (o'clock) with 시간 (duration) after 후. "In two hours" is a duration — 두 시간 후 — not the clock point 두 시.

• ✗ 두 시 후에 봐요.
• ✓ 두 시간 후에 봐요. — du sigan hue bwayo — "See you in two hours."

5. Dropping 에 when placing an event. To say something happens at half past ten, the time still needs 에: 열 시 반에.

• ✗ 열 시 반 잘게요.
• ✓ 열 시 반에 잘게요. — yeol si bane jalgeyo — "I'll sleep at ten thirty."

Key Takeaways

• 반 = half past (두 시 반 = 2:30), a native-neutral stand-in for 삼십 분 and the default in casual speech.
• 전 = before/to, a postposition that assembles in Korean order: [hour] 시 [minutes] 분 전 — 세 시 오 분 전, never the English ×오 분 전 세 시.
• 후 = after, used mostly for durations with 시간 (한 시간 후), counting forward from now; add 에 to place the event.
• 정각 = on the dot (다섯 시 정각), a slightly formal punctuality marker.
• The minutes inside these expressions stay Sino (오 분 전), and 후 pairs with the duration counter 시간, not the clock counter 시.