Numbers: The Most Useful Vocabulary You'll Ever Learn
Prices, train times, phone numbers, ages, dates — numbers are everywhere, and the great news is that Japanese numbers are wonderfully logical. Learn 0–10 and you can build almost every number up to 99,999,999 with simple stacking rules. In this chapter you'll master counting, telling the time, dates, and get your first taste of Japan's famous counter words.
1. Zero to Ten
| Number | Kanji | Reading | Romaji |
|---|---|---|---|
| 0 | 〇 / ゼロ | れい・ゼロ | rei / zero |
| 1 | 一 | いち | ichi |
| 2 | 二 | に | ni |
| 3 | 三 | さん | san |
| 4 | 四 | よん・し | yon / shi |
| 5 | 五 | ご | go |
| 6 | 六 | ろく | roku |
| 7 | 七 | なな・しち | nana / shichi |
| 8 | 八 | はち | hachi |
| 9 | 九 | きゅう・く | kyū / ku |
| 10 | 十 | じゅう | jū |
Why do 4, 7 and 9 have two readings? The default modern readings are yon, nana, kyū. The alternatives し (shi) and く (ku) survive in fixed contexts (like some months and times below). Fun cultural fact: し sounds like 死 (death) and く like 苦 (suffering), so Japanese hospitals and hotels often skip room numbers 4 and 9 — just like Western buildings skip floor 13!
2. Building Bigger Numbers
Japanese numbers stack like arithmetic:
- 11–19 = "ten + digit": 11 = じゅういち (jū-ichi), 12 = じゅうに (jū-ni), … 19 = じゅうきゅう (jū-kyū)
- 20, 30… = "digit + ten": 20 = にじゅう (ni-jū), 30 = さんじゅう (san-jū), … 90 = きゅうじゅう (kyū-jū)
- Combine both: 25 = にじゅうご (ni-jū-go, "two-ten-five"), 78 = ななじゅうはち (nana-jū-hachi)
Hundreds and thousands work the same, with a few sound changes (marked in bold) that exist purely to make words easier to say:
| Hundreds (百) | Reading | Thousands (千) | Reading |
|---|---|---|---|
| 100 | ひゃく (hyaku) | 1,000 | せん (sen) |
| 300 | さんびゃく (sanbyaku) | 3,000 | さんぜん (sanzen) |
| 600 | ろっぴゃく (roppyaku) | 6,000 | ろくせん (rokusen) |
| 800 | はっぴゃく (happyaku) | 8,000 | はっせん (hassen) |
All other hundreds/thousands are perfectly regular: 200 = にひゃく, 500 = ごひゃく, 2,000 = にせん, and so on.
The 万 (man) system: thinking in ten-thousands
Here is the one genuinely different habit: where English groups big numbers by thousands (10 thousand, 100 thousand, 1 million), Japanese groups by ten-thousands (万, man):
| Number | Japanese | Think of it as… |
|---|---|---|
| 10,000 | いちまん (ichiman) | 1 man |
| 100,000 | じゅうまん (jūman) | 10 man |
| 1,000,000 | ひゃくまん (hyakuman) | 100 man (a million = "hundred man"!) |
For everyday life you mostly need up to 万 — a nice dinner might be 3,500円 (さんぜんごひゃくえん), a hotel night 12,000円 (いちまんにせんえん). Prices attach 円 (えん, en — yen) directly to the number.
3. Telling Time
Time is number + 時 (ji, o'clock), with minutes as number + 分 (fun/pun):
| Hour | Reading | Hour | Reading |
|---|---|---|---|
| 1時 | いちじ (ichiji) | 7時 | しちじ (shichiji) |
| 2時 | にじ (niji) | 8時 | はちじ (hachiji) |
| 3時 | さんじ (sanji) | 9時 | くじ (kuji) |
| 4時 | よじ (yoji) | 10時 | じゅうじ (jūji) |
| 5時 | ごじ (goji) | 11時 | じゅういちじ (jūichiji) |
| 6時 | ろくじ (rokuji) | 12時 | じゅうにじ (jūniji) |
Three hours are irregular — memorize よじ (4:00), しちじ (7:00), くじ (9:00). Never "yonji" or "kyūji"!
Minutes alternate between ふん (fun) and ぷん (pun) depending on the preceding sound:
| Minutes | Reading | Minutes | Reading |
|---|---|---|---|
| 1分 | いっぷん (ippun) | 6分 | ろっぷん (roppun) |
| 2分 | にふん (nifun) | 7分 | ななふん (nanafun) |
| 3分 | さんぷん (sanpun) | 8分 | はっぷん (happun) |
| 4分 | よんぷん (yonpun) | 9分 | きゅうふん (kyūfun) |
| 5分 | ごふん (gofun) | 10分 | じゅっぷん (juppun) |
Useful extras: 半 (han) = half past → 3時半 (sanji han, 3:30). 午前 (gozen) = a.m., 午後 (gogo) = p.m. → 午後7時 (gogo shichiji, 7 p.m.). Asking the time: いま何時ですか (ima nanji desu ka) — "What time is it now?"
4. The Calendar
Days of the week
You met these in the kanji chapter — here's the full set for review: 月曜日 (getsuyōbi, Mon), 火曜日 (kayōbi, Tue), 水曜日 (suiyōbi, Wed), 木曜日 (mokuyōbi, Thu), 金曜日 (kin'yōbi, Fri), 土曜日 (doyōbi, Sat), 日曜日 (nichiyōbi, Sun). Asking: 今日は何曜日ですか (kyō wa nan'yōbi desu ka) — "What day is it today?"
Months: beautifully simple
Months are just number + 月 (gatsu). January = 一月 (ichigatsu), February = 二月 (nigatsu)… The only ones needing care use the alternate number readings:
- April = 四月 しがつ (shigatsu) — not "yongatsu"
- July = 七月 しちがつ (shichigatsu)
- September = 九月 くがつ (kugatsu) — not "kyūgatsu"
Days of the month: the tricky ones
From the 11th onward, days are mostly number + にち (nichi): 11日 = じゅういちにち, 25日 = にじゅうごにち. But days 1–10 (plus a few others) use an older native counting system — these must be memorized:
| Day | Reading | Day | Reading |
|---|---|---|---|
| 1日 | ついたち (tsuitachi) | 6日 | むいか (muika) |
| 2日 | ふつか (futsuka) | 7日 | なのか (nanoka) |
| 3日 | みっか (mikka) | 8日 | ようか (yōka) |
| 4日 | よっか (yokka) | 9日 | ここのか (kokonoka) |
| 5日 | いつか (itsuka) | 10日 | とおか (tōka) |
Also irregular: 14日 じゅうよっか (jūyokka), 20日 はつか (hatsuka), 24日 にじゅうよっか (nijūyokka). Careful with the sound-alikes: 8日 ようか vs 4日 よっか — that small っ is the difference between the 8th and the 4th!
Relative time words
| Japanese | Romaji | Meaning | Japanese | Romaji | Meaning |
|---|---|---|---|---|---|
| 今日 | kyō | today | 今 | ima | now |
| 昨日 | kinō | yesterday | 今朝 | kesa | this morning |
| 明日 | ashita | tomorrow | 今晩 | konban | tonight |
| 先週 | senshū | last week | 毎日 | mainichi | every day |
| 今週 | konshū | this week | 毎朝 | maiasa | every morning |
| 来週 | raishū | next week | 毎晩 | maiban | every night |
| 先月 | sengetsu | last month | 去年 | kyonen | last year |
| 来月 | raigetsu | next month | 来年 | rainen | next year |
Spot the pattern: 先 (sen/last) — 今 (kon/this) — 来 (rai/next), combined with 週 (shū, week) and 月 (getsu, month): 先週・今週・来週, 先月・今月・来月. The year column is partly irregular — last year is 去年 (kyonen, not ✗先年), this year is 今年 with the special reading kotoshi, and only 来年 (rainen) follows the pattern.
5. Counters: Japan's Counting Words
In English we say "two sheets of paper" and "three cups of coffee". Japanese does this for everything: numbers attach a counter word that matches what's being counted. There are many counters, but these five cover most beginner situations:
| Counter | Used for | Examples |
|---|---|---|
| 〜つ (tsu) | general things (the universal fallback, 1–10 only) | ひとつ, ふたつ, みっつ, よっつ, いつつ, むっつ, ななつ, やっつ, ここのつ, とお |
| 〜人 (nin) | people | ひとり (1), ふたり (2), さんにん (3), よにん (4), ごにん (5)… |
| 〜本 (hon/bon/pon) | long thin things: bottles, pens, umbrellas | いっぽん (1), にほん (2), さんぼん (3)… |
| 〜枚 (mai) | flat things: paper, tickets, shirts | いちまい, にまい, さんまい… (fully regular!) |
| 〜匹 (hiki/biki/piki) | small animals: cats, dogs, fish | いっぴき (1), にひき (2), さんびき (3)… |
Notice ひとつ・ふたつ・みっつ — this is the old native counting system, the same one behind ついたち・ふつか・みっか in dates. It all connects!
Beginner strategy: when you don't know the right counter, use 〜つ for things and nobody will blink: りんごをみっつください (ringo o mittsu kudasai) — "three apples, please." The counter goes after the object+particle, right before the verb. You'll practice this pattern properly in the Grammar section.
6. Practice Round
Cover the answers and try these out loud:
| Say in Japanese… | Answer |
|---|---|
| 365 | さんびゃくろくじゅうご (sanbyaku rokujū go) |
| 4:30 p.m. | ごご よじはん (gogo yoji han) |
| 9:15 | くじ じゅうごふん (kuji jūgofun) |
| July 8th | しちがつ ようか (shichigatsu yōka) |
| April 1st | しがつ ついたち (shigatsu tsuitachi) |
| 2,980 yen | にせんきゅうひゃくはちじゅうえん (nisen kyūhyaku hachijū en) |
| two people | ふたり (futari) |
| every morning at 7:00 | まいあさ しちじ (maiasa shichiji) |
Summary & Key Takeaways
- Numbers stack logically: 25 = "two-ten-five" (にじゅうご). Defaults for 4/7/9 are yon/nana/kyū.
- Sound changes to memorize: さんびゃく 300, ろっぴゃく 600, はっぴゃく 800, さんぜん 3,000, はっせん 8,000.
- Big numbers group by 万 (10,000): one million = ひゃくまん ("100 man").
- Time = number + 時; irregular hours: よじ, しちじ, くじ. Minutes alternate ふん/ぷん; 半 = half past; 午前/午後 = a.m./p.m.
- Months = number + 月, with しがつ (Apr), しちがつ (Jul), くがつ (Sep). Days 1–10 are special: ついたち, ふつか, みっか… plus じゅうよっか (14th) and はつか (20th).
- Relative time is systematic: 先/今/来 + 週/月/年.
- Counting needs counters: 〜つ for things (universal fallback), 〜人 for people (ひとり, ふたり!), 〜本 long things, 〜枚 flat things, 〜匹 small animals.