Numbers in Korean: Two Complete Systems, and When to Use Each

Korean numbers are not hard. They are double. The language runs two complete counting systems side by side, and using the wrong one is not a small slip, it is the equivalent of saying "I am three-th years old". Sino-Korean (일, 이, 삼) handles money, dates, phone numbers and minutes. Native Korean (하나, 둘, 셋) handles hours, ages and counting objects.

This is the complete reference: both full tables with native audio, the division of labour, the irregularity nobody warns you about, counters, big numbers, ordinals and fractions. Bookmark it and you will not need another page.

The short answer: for money and minutes, 1 is 일▶. For hours, ages and objects, 1 is 하나▶. 100 is 백▶, and 10,000 is 만▶. Now the detail.

Which System for What

Memorise this table and the rest is mechanics.

Look closely at time. 3:30 is 세 시 삼십 분: native for the hour, Sino for the minutes, in the same breath. That is not a trick question, that is just how Koreans tell the time, and it is the clearest proof you cannot pick a favourite system and ignore the other.

System 1: Sino-Korean (Complete Table)

Borrowed from Chinese, used for anything measured. Perfectly regular: ten words build everything.

Sino-Korean 1 to 100

1 to 20

21 to 40

41 to 60

61 to 80

81 to 100

Note the shortcut: 10 is 십 (sip), not 일십. You never say "one ten". But 20 is 이십 (isip), "two ten". Only the first ten drops its il.

System 2: Native Korean (Complete Table)

Older, homegrown, used for counting things, hours and ages.

The native tens: 열▶ (10), 스물▶ (20), 서른▶ (30), 마흔▶ (40), 쉰▶ (50), 예순▶ (60), 일흔▶ (70), 여든▶ (80), 아흔▶ (90). Combine them the obvious way: 47 is 마흔일곱▶ (maheun ilgop), 99 is 아흔아홉▶ (aheun ahop).

But the system stops at 99. There is no native word for one hundred. Above that, everyone switches to Sino, always. And in practice most Koreans abandon native numbers well before 99: nobody counts to sixty in native Korean by choice, though ages still use them right up to 아흔 and beyond.

The Irregularity Nobody Warns You About

The first four native numbers, plus twenty, change shape when a counter follows:

So you count hana, dul, set out loud in the abstract, but the moment you attach the thing you are counting, they shorten. This is the single most common learner error in Korean numbers, and natives notice it immediately.

Counters

Like Japanese and Chinese, Korean cannot count a noun bare. The ones that actually matter day to day:

Learn 개 and 명 first and you can survive almost anything.

Big Numbers Group by Ten Thousand

Same trap as Chinese and Japanese. Korean's unit is 만▶ man (10,000), and everything scales from it.

Korean prices are large by default, so this is not academic: a 30,000 won meal is 삼만 원▶ samman won, "three man won". Learners who group in thousands stall at every restaurant. An annual salary of 50,000,000 won is 오천만 원, "five thousand man".

Note that unlike English, you do not say 일백 for 100 or 일천 for 1000. Just 백 and 천. But 10,000 keeps its 일: 일만 or just 만.

Ordinal Numbers

Native numbers plus 번째▶ beonjjae:

Only the first is irregular: it is 첫, not 하나. And notice the shortened forms again: 두, 세, 네.

For formal or written contexts, Sino ordinals exist with 제 je: 제1회, "the 1st edition".

Fractions, Decimals and Percentages

Fractions run backwards to English, like Chinese and Japanese: sabunui sam is "of four parts, three". Denominator first. And 반▶ ban is the everyday word for half: 반 시간, half an hour.

Zero has two words: 영▶ yeong (maths, decimals) and 공▶ gong (phone numbers, sports scores).

Pronunciation: What the Romanization Hides

Three details do most of the work.

Korean consonants reshape at word boundaries. 십일 (11) is written sip-il but pronounced 시빌 sibil: the final ㅂ slides into the next syllable. This happens everywhere and Revised Romanization only sometimes shows it. Read the numbers as written and you will be understood, but you will not recognise them when spoken.

여덟 (8) drops a letter. It is written with a final ㄹㅂ cluster but pronounced yeodeol. The ㅂ is silent. Nobody tells beginners this.

육 (6) mutates. In 16, 십육 is pronounced 심뉵 simnyuk, not sib-yuk. A whole n appears from nowhere. This is regular Korean phonology, not an exception, but it is invisible on the page. Same with 백만 (1,000,000), pronounced baengman, not baekman.

This is exactly where written guides run out of road. Romanization can spell sip-il, but the word is sibil, and a number you have only ever read is a number you will not catch at a till in Seoul. The only fix is to hear a native say the whole thing, then say it back out loud, several times, until it stops being decoding. That listen and repeat loop is called shadowing, and it is what turns 스물다섯 from four syllables you assemble into one word you simply say. It is how the Hyperpolyglot app handles every phrase: real sentences, native audio, looped until they come out automatically. Available on iOS, Android, and Web.

The Numbers Korea Treats as Special

• 4 is avoided, exactly as in China and Japan: 사 (sa) sounds like 死, death. Lifts label the fourth floor F instead of 4, hospitals skip it, and some buildings jump from 3 to 5.
• Korean age used to be its own system. Until a 2023 law standardised on international age, Koreans counted themselves as 1 at birth and added a year every 1 January, so a baby born on 31 December turned 2 the next day. Older people still use it socially, so 한국 나이 ("Korean age") is still worth knowing.
• Anniversaries in units of 100 days. Couples celebrate 백일▶ (baegil, 100 days) together, then 200, then 1000. Asking a Korean couple their baegil date is entirely normal.
• 빼빼로▶ day is 11 November (11/11), named for the four stick-shaped ones in the date.
• Phone numbers use 공 (gong) for zero, not 영.

Common Mistakes to Avoid

1. Using Sino numbers for hours. 일 시 is not one o'clock. It is 한 시.
2. Saying 하나 개. Before a counter it is 한 개. The first four always shorten, plus 스물.
3. Using native numbers for money. Prices are always Sino: 오천 원.
4. Reading 십육 as sib-yuk. It is simnyuk.
5. Grouping big numbers by thousands. The unit is 만, ten thousand.
6. Saying 일백 for 100. Just 백.
7. Counting past 99 in native Korean. It does not go there. Switch to Sino.

The Numbers You Will Actually Use First

• Ordering: 이거 두 개 주세요▶, "two of these please".
• Price: 얼마예요?▶, "how much is it?"
• Age: 스물다섯 살이에요▶, "I'm twenty-five".
• Time: 세 시 삼십 분▶, "3:30", the two systems in one breath.
• People: 네 명이요▶, "four of us", walking into a restaurant.

Learn both tens tables, tattoo "hours native, minutes Sino" somewhere visible, and remember the first four numbers shorten. Drill them with real audio until they arrive as sounds rather than lookups, and Korean's double system turns from a burden into a pattern.

Keep Reading

• Language Islands -- the real-sentence method that turns vocabulary into actual conversations
• The Shadowing Technique -- how to drill pronunciation until it becomes automatic
• How to Learn Multiple Languages at the Same Time