Numbers look like the easy part of Japanese, right up until you try to order two coffees and discover that "two" changes shape depending on what you're counting. Here's the practical version: the counting system itself, then the counters, then the small set worth memorizing first.
1 to 10
| Number | Kanji | Reading |
|---|---|---|
| 1 | 一 | いち |
| 2 | 二 | に |
| 3 | 三 | さん |
| 4 | 四 | よん / し |
| 5 | 五 | ご |
| 6 | 六 | ろく |
| 7 | 七 | なな / しち |
| 8 | 八 | はち |
| 9 | 九 | きゅう / く |
| 10 | 十 | じゅう |
Why 4, 7, and 9 have two readings: し (4) sounds like 死 "death" and く (9) like 苦 "suffering", so よん and きゅう became the everyday defaults. しち (7) survives in fixed phrases and times. Rule of thumb for beginners: use よん, なな, きゅう unless you're reading a time or a set expression.
11 to 99 — just addition
Japanese numbers are refreshingly regular. Build them literally:
- 11 = 十一 (じゅういち) — "ten one"
- 20 = 二十 (にじゅう) — "two ten"
- 45 = 四十五 (よんじゅうご) — "four ten five"
- 99 = 九十九 (きゅうじゅうきゅう)
No irregular teens, no "forty" vs "four". Once you know 1–10 and 十, you have every number up to 99.
100 and beyond
- 100 = 百 (ひゃく) — watch the sound changes: 300 is さんびゃく, 600 ろっぴゃく, 800 はっぴゃく
- 1,000 = 千 (せん) — 3,000 is さんぜん, 8,000 はっせん
- 10,000 = 万 (まん) — this is the one that trips English speakers
Japanese groups large numbers in units of 10,000, not 1,000. So 100,000 isn't "hundred thousand" but 十万 (ten man), and a million is 百万 (hundred man). Converting on the fly is genuinely awkward at first; it becomes automatic with exposure, and prices in yen give you daily practice.
Counters: the actual difficulty
You can't say "two apples" in Japanese with a bare number. You need a counter — a suffix that says what kind of thing you're counting. English does this occasionally ("two sheets of paper", "three head of cattle"); Japanese does it always.
The ones worth learning first:
- 〜つ — the universal fallback for objects: ひとつ, ふたつ, みっつ… up to ここのつ, then とお. Irregular, but it works for almost anything physical when you don't know the right counter. Learn this one first.
- 〜人 (にん) — people. Note 一人 (ひとり) and 二人 (ふたり) are irregular; from 三人 (さんにん) it's regular.
- 〜個 (こ) — small objects. Broad and safe.
- 〜枚 (まい) — flat things: paper, tickets, shirts, pizza.
- 〜本 (ほん) — long cylindrical things: bottles, pens, umbrellas. Sound-changes a lot: いっぽん, にほん, さんぼん.
- 〜杯 (はい) — cupfuls and glassfuls. This is the one for ordering drinks.
- 〜匹 (ひき) — small animals; 〜頭 (とう) for large ones.
- 〜台 (だい) — machines and vehicles.
- 〜歳 / 〜才 (さい) — age. 二十歳 (はたち) for 20 is irregular and very common.
There are dozens more, including genuinely odd ones (rabbits are traditionally counted with 羽, the counter for birds). You do not need them. Native speakers fall back on 〜つ and 〜個 more than textbooks admit.
The sound changes
Counters starting with h-, k-, or s- often shift after 1, 3, 6, 8, and 10 — いっぽん, ろっぴき, はっぱい. Don't memorize a table. These are exactly the patterns that stick through hearing and repetition rather than study, which is why counters belong in your regular review rotation with real example sentences rather than in a chart you re-read.
What to actually do first
- Master 1–10, then the addition rules to 99. That's an afternoon.
- Learn 〜つ and 〜人 properly, including the irregular forms.
- Add 枚, 本, 個, 杯 as you meet them.
- Get comfortable with 万 by reading yen prices.
- Let the rest arrive through exposure.
Numbers and counters are pure high-frequency vocabulary — the kind of thing that pays back immediately and then keeps paying. That's exactly what Cotobara drills: common words in JLPT and frequency order, each with a level-appropriate example sentence and natural-sounding audio, so the sound changes get into your ear rather than staying on a chart. For the wider beginner picture, see how to start learning Japanese.
Start Cotobara for free — numbers, counters, and the rest of the words you'll actually use.