Ages use native numbers with 살
Say an age with a native number and the counter 살: 스무 살 (20), 서른세 살 (33), 마흔한 살 (41).
살 is a counter, so the short forms apply: 하나, 둘, 셋, 넷 become 한, 두, 세, 네, and 스물 becomes 스무. With a ones digit only the last part shortens, which is why 33 is 서른세 살.
The native tens
Ages above 10 are built on the native tens. Watch 마흔 (40) and 쉰 (50) in particular; they are easy to mix up.
| Number | Native |
|---|---|
| 10 | 열 |
| 20 | 스물 |
| 30 | 서른 |
| 40 | 마흔 |
| 50 | 쉰 |
| 60 | 예순 |
| 70 | 일흔 |
| 80 | 여든 |
| 90 | 아흔 |
Formal ages with 세
On forms and in the news, ages are often written with 세 instead of 살. 세 goes with Sino-Korean numbers, so you say 마흔두 살 in conversation and see 42세 on paper. Mixing the two, as in 사십두 살, sounds awkward.
Common mistakes with ages
| You might say | Say | Why |
|---|---|---|
| 스물 살 | 스무 살 | 20 shortens to 스무 before 살 |
| 이십 살 | 스무 살 | 살 takes native numbers |
| 서른셋 살 | 서른세 살 | Shorten the last part: 셋 becomes 세 |
| 쉰한 살 | 마흔한 살 | 마흔 is 40 and 쉰 is 50 |