백일 (baegil)

백일 (baegil) means the hundredth day counting from the day a child was born. It points to that one single day — the day a baby has been in the world for exactly one hundred days. In Korea, that day doesn’t just slip by. Families steam white 백설기 (baekseolgi) rice cake, take the baby to a photo studio, and hand out rice cake to neighbors and relatives. The table set in front of the baby, laid with rice cake and fruit, is called a 백일상 (baegilsang), and the celebration held around it is a 백일잔치 (baegiljanchi).

Korean learners tend to pause at this word. It isn’t a birthday, and 100 isn’t a especially big round unit in Korean, so why hand out rice cake on the hundredth day of all days? 백일 isn’t just a way of counting days. It’s the first knot Koreans tie into a child’s life. Once you know why that knot exists, the word is hard to forget.

Its range of use is narrow, but its borders are very sharp. First, the subject is almost always a baby. You never attach 백일 to an adult. Second, the closed-up single word 백일 (baegil) and the spaced-out 백 일 (baek il) mean different things. The first is a baby’s milestone; the second is simply a span of 100 days. Third, the temperature is bright. It only comes out in settings where congratulation mixes with relief, so it doesn’t sit well in sad or heavy sentences.

The words that branch off this one are worth memorizing together: 백일상 (baegilsang) (the table setting), 백일잔치 (baegiljanchi) (the gathering), 백일 사진 (baegil sajin) (the commemorative photo taken at a studio), and 백일 떡 (baegil tteok) (the white rice cake that gets handed out). Nearly every Korean parent’s phone photo album contains all four.

Checking the National Institute of Korean Language dictionary

백일 「명사」 (noun) 아이가 태어난 날로부터 백 번째 되는 날. The hundredth day counting from the day a child was born. [en] baegil — one hundredth day: The hundredth day of a baby’s birth. [ja] ひゃくにち【百日】 — 子供が生まれた日から100日目の日。 [es] 100 días de nacimiento — Fecha en que se cumplen los 100 días de nacimiento de un bebé. [zh] 百日，百天 — 婴儿出生后的第一百天。 — National Institute of Korean Language, Basic Korean Dictionary (krdict.korean.go.kr)

A Portuguese gloss isn’t carried in this dictionary. The line below is not a dictionary quotation but our own rendering — centésimo dia: o centésimo dia contado desde o nascimento de um bebê.

Below are the real usage examples the dictionary carries, quoted as they are, each with a note on what kind of situation the sentence belongs to.

백일이 조금 지나자 아기는 누운 채로 도리질을 하기 시작했다. (baegiri jogeum jinaja agineun nuun chaero dorijireul hagi sijakhaetda) A little past the hundredth day, the baby began shaking its head from side to side while lying down. — National Institute of Korean Language, Basic Korean Dictionary (krdict.korean.go.kr)

This is the most typical use of 백일 as a reference point in time. When Korean parents talk about a baby’s development, they often divide the timeline into before and after 백일 rather than counting months.

아기는 백일이 지나면 고개를 어느 정도 똑바로 들 수 있게 된다. (agineun baegiri jinamyeon gogaereul eoneu jeongdo ttokbaro deul su itge doenda) Once a baby passes the hundredth day, it becomes able to hold its head up fairly straight. — National Institute of Korean Language, Basic Korean Dictionary (krdict.korean.go.kr)

This is the kind of sentence you’d find in a parenting book or a pediatrician’s handout. Since babies gain head control around this time, 백일 really is a line where a baby’s body visibly changes.

지수는 비디오로 녹화한 조카의 백일잔치 동영상을 개인 홈페이지에 올렸다. (Jisuneun bidioro nokhwahan jokaui baegiljanchi dongyeongsangeul gaein hompeijie ollyeotda) Ji-su uploaded the video she had recorded of her nephew’s hundredth-day party to her personal homepage. — National Institute of Korean Language, Basic Korean Dictionary (krdict.korean.go.kr)

Here 백일 appears with 잔치 attached. It’s also worth noticing that the subject isn’t a parent but an aunt or uncle. A 백일잔치 isn’t just the parents’ event — it’s an occasion where both sides of the family gather.

어머니는 구십 일째 백일기도를 하고 계신다. (eomeonineun gusip iljjae baegilgidoreul hago gyesinda) Mother is on the ninetieth day of her hundred-day prayer. — National Institute of Korean Language, Basic Korean Dictionary (krdict.korean.go.kr)

The 백일 here has nothing to do with a baby. A prayer offered for a hundred days in a row without missing a single day is called a 백일기도 (baegilgido). The phrase “on the ninetieth day” carries the feeling of only ten more to go.

내가 기안한 교내 백일장 행사가 다음 학기에 열리기로 결정되었다. (naega gianhan gyonae baegiljang haengsaga daeum hakgie yeolligiro gyeoljeongdoeeotda) The school-wide writing contest I drafted the proposal for was decided to be held next semester. — National Institute of Korean Language, Basic Korean Dictionary (krdict.korean.go.kr)

백일장 (baegiljang) is a separate word listed on its own in the dictionary, meaning a writing contest. It has nothing to do with a baby’s 백일. This is where learners get confused most often, so it’s better to memorize 백일장 as one whole word.

Seeing it in a real conversation

Situation: Saturday morning, the living room at Jun-kyung’s place. Today is his daughter’s hundredth day. The table is being set, and Emily has just walked in carrying a box of rice cake.

준경: 왔어? 손 씻고 이것 좀 잡아 줘. 상보가 자꾸 밀려. You’re here? Wash your hands and hold this for me. The cloth keeps sliding.

에밀리: 알았어. 근데 떡집에서 이만큼 주던데, 이거 다 우리가 먹어? Okay. But the rice-cake shop gave me this much — are we eating all of it?

준경: 아니지. 백일 떡은 여러 집에 나눠야 애가 오래 산대. 옆집이랑 경비실도 갖다드려야 돼. No way. They say baegil rice cake has to be shared around so the baby lives long. We have to take some to the neighbors and the security office too.

에밀리: 아, 그래서 흰 떡만 잔뜩이구나. 난 그냥 잔치 음식인 줄 알았네. Ah, that’s why it’s all plain white rice cake. I just thought it was party food.

준경: 옛날엔 백일을 못 넘기는 아기가 많았거든. 이제 한 고비 넘겼다, 그런 뜻이야. Long ago a lot of babies didn’t make it past a hundred days. It means we’ve gotten over one hurdle.

에밀리: 그 말 들으니까 갑자기 상이 다르게 보인다. 사진은 찍었어? Hearing that, this table suddenly looks different to me. Did you take the photos?

준경: 어제 백일 사진 찍고 왔는데, 애가 내내 울어서 백 장 찍고 두 장 건졌어. We got the baegil photos yesterday, but she cried the whole time — a hundred shots, two keepers.

Using it this way sounds off

✗ 이 프로젝트 끝내는 데 백일 걸렸어. (i peurojekteu kkeutnaeneun de baegil geollyeosseo) ✓ 이 프로젝트 끝내는 데 백 일 걸렸어. / 100일 걸렸어. (i peurojekteu kkeutnaeneun de baek il geollyeosseo / 100-il geollyeosseo) It took a hundred days to finish this project. → Written closed up, 백일 is a single word meaning a baby’s milestone. Use it as-is for a span of time and your listener will briefly think you’re talking about a baby. In speech, too, 백 일 is read with a beat of space between the syllables.

✗ (to a parent who didn’t hold a 백일잔치) 요즘도 백일은 다 하던데, 왜 안 하세요? (yojeumdo baegireun da hadeonde, wae an haseyo?) Everyone still does the hundredth day these days — why aren’t you? ✓ (to a parent who didn’t hold a 백일잔치) 아기 백일 지났죠? 사진이라도 남기셨어요? (agi baegil jinatjyo? sajinirado namgisyeosseoyo?) Your baby’s past the hundredth day, right? Did you at least get some photos? → The grammar is fine, but the timing is off. These days plenty of families skip the party and just eat together, or skip it entirely, and there can be reasons behind that decision. 백일 is a word you bring out to congratulate — not to check up on someone or call them out.

Example sentences by situation

1) Taking a half day off at work — a moment for telling your team lead the reason briefly and clearly. At a Korean company, a baby’s 백일 is generally a reason that passes without further comment.

다음 주 금요일에 아기 백일이라 반차 좀 쓰겠습니다. (daeum ju geumyoire agi baegilira bancha jom sseugetseumnida) Our baby’s hundredth-day is next Friday, so I’d like to take a half day.

2) Handing rice cake over at a neighbor’s door — this might be a neighbor you’re meeting for the first time. No long explanation needed; this one sentence is enough.

저희 아기 백일이라 떡 좀 나눠 드리려고요. (jeohui agi baegilira tteok jom nanwo deuriryeogoyo) It’s our baby’s hundredth day, so I wanted to share some rice cake with you.

3) To a friend you haven’t seen in a while — when asking after someone’s baby, 백일 makes a natural reference point for the question.

너희 애 백일은 지났지? 벌써 백 일이라니 시간 진짜 빠르다. (neohui ae baegireun jinatji? beolsseo baek irirani sigan jinjja ppareuda) Your baby’s past the hundredth day, right? A hundred days already — time really flies.

Polite and casual forms, and similar expressions

백일 itself is a noun, so it carries no honorific level of its own. Polite versus casual is decided by the predicate that follows it.

Casual: 다음 주가 우리 애 백일이야 (baegiriya)
Everyday polite: 다음 주가 저희 아기 백일이에요 (baegirieyo)
Formal: 다음 주가 저희 아이 백일입니다 (baegirimnida)

Expressions that look similar break down like this.

Expression	Temperature / intensity	Where it’s used
백일 (baegil)	Warm and celebratory	A baby 100 days old. Congratulations and handing out rice cake
돌 (dol)	Bigger and more formal than 백일	The first birthday. Invitations go out and the party is the largest
삼칠일 (samchiril)	Quiet, old-fashioned	21 days after birth. Barely used in conversation today
백 일 (baek il)	Neutral, just a span of time	A count of 100 days. Any sentence unrelated to a baby
100일 (baegil)	Light and casual	Written as a numeral — a couple’s 100th day together, 100 days into military service

Cultural background — the heart behind counting a hundred days

The word 백일 has a completely transparent structure. 백 (百, hundred) and 일 (日, day) are simply stuck together; there’s no hidden metaphor. And yet the reason this flat little number became a milestone lies outside the number itself. In an era when medicine wasn’t what it is now, it wasn’t rare for a newborn to fail to survive its first few months. So old Korean childrearing customs did not show a baby to the outside world right away. Until 삼칠일 (samchiril), the twenty-first day after birth, a 금줄 (geumjul) — a taboo rope — was hung across the front gate and outsiders refrained from entering; only after a hundred days had passed did the family finally carry the baby out before other people. A 백일잔치 was, in that sense, an occasion of relief at having cleared the first hurdle.

That’s also why white 백설기 (baekseolgi) is used as the 백일 rice cake. A saying has long been passed down that if you steam plain white rice cake with nothing mixed in and share it with as many households as possible, the baby will live a long life free of illness. Even now there are parents who walk the apartment corridors hanging rice cake on neighbors’ door handles, and the custom of never returning the plate empty when you receive that rice cake still survives.

Today’s 백일 has shrunk considerably in scale. Instead of a big party, most families just take 백일 photos at a studio and finish with a single meal among relatives. In exchange, the form has actually grown more elaborate — photo studios now offer hundredth-day shoot packages, and there are even rental services just for 백일상 tables. 백일잔치 scenes still turn up often in dramas, though usually not to show off the baby: they serve as a stage where the whole family gathers in one place for the first time in ages and long-buried conflicts erupt. The 백일상 is the most convenient assembly point in Korean drama.

Meanwhile, the word 백일 has stretched beyond babies as well. There’s 백일기도, praying for a hundred days straight; the military’s 100-day leave, which promises something a hundred days out; the 100-day anniversary couples mark — for Koreans, a hundred days is a familiar yardstick for measuring one hurdle. The 백일 in a title like the tvN drama 《백일의 낭군님》 (Baegirui Nanggunnim, “100 Days My Prince”, tvN, 2018) also refers to this span of a hundred days, not to a baby. That said, these uses are usually written with the numeral 100일, and the closed-up 백일 still belongs to babies.

Today’s quiz

Which of the following sentences uses 백일 naturally?

① 이 보고서 쓰는 데 백일 걸렸어요. (i bogoseo sseuneun de baegil geollyeosseoyo) It took a hundred days to write this report.

② 조카가 다음 주에 백일이라 떡 돌린대요. (jokaga daeum jue baegirira tteok dollindaeyo) My nephew’s hundredth day is next week, so they say they’re handing out rice cake.

③ 할아버지, 백일 축하드려요. (harabeoji, baegil chukhadeuryeoyo) Grandfather, congratulations on your hundredth day.

The answer is ②. Sentence ① is talking about a span of time, so it needs to be spaced as 백 일 or written with numerals as 100일. Sentence ③ doesn’t work because 백일 is only used for babies — an adult’s birthday is simply 생신 (saengsin). Only ② matches the dictionary definition exactly: a baby reaching the hundredth day since being born.

Definitions and example sentences are from the National Institute of Korean Language’s Basic Korean Dictionary (krdict.korean.go.kr); that portion of this post, including our translations, is licensed under CC BY-SA 2.0 KR.