Here's the secret this guide is built on: the system is far more regular than it looks. There are two number systems with clear jobs, about a dozen counters that cover 90% of daily life, and the "random" pronunciation changes follow just three sound rules. Learn the rules instead of memorizing hundreds of forms, and counting becomes one of the most satisfying systems in the language.
The Two Number Systems
Japanese inherited two complete ways to count: the native Japanese system and the Sino-Japanese (Chinese-origin) system.
Sino-Japanese numbers (the main system)
| Number | Reading | Number | Reading |
|---|---|---|---|
| 1 | いち ichi | 7 | しち/なな shichi/nana |
| 2 | に ni | 8 | はち hachi |
| 3 | さん san | 9 | きゅう/く kyuu/ku |
| 4 | し/よん shi/yon | 10 | じゅう juu |
| 5 | ご go | 100 | ひゃく hyaku |
| 6 | ろく roku | 1000 | せん sen |
Bigger numbers stack logically: 11 = じゅういち (10+1), 20 = にじゅう (2×10), 345 = さんびゃくよんじゅうご. Japanese groups large numbers by 10,000 (万 man), not 1,000: 1万 = 10,000, 10万 = 100,000, 100万 = 1,000,000, 1億 (oku) = 100,000,000.
The 4/7/9 situation: し (4) sounds like 死 (death) and く (9) like 苦 (suffering), so よん and きゅう are preferred in most contexts. しち (7) is easily misheard as いち, so なな often wins. Hospitals famously avoid rooms numbered 4 and 9.
| Context | 4 | 7 | 9 |
|---|---|---|---|
| Counting up (abstract) | し or よん | しち or なな | く or きゅう |
| Phone numbers, prices | よん | なな | きゅう |
| April, July, September | しがつ | しちがつ | くがつ |
| 4 o'clock / 9 o'clock | よじ | しちじ | くじ |
Months and o'clock are fixed — memorize those four bolded readings; they are tested on every JLPT N5.
Native Japanese numbers (ひとつ, ふたつ…)
The native system survives mainly as the universal counter つ (1–10 only):
| Number | Native | Number | Native |
|---|---|---|---|
| 1 | ひとつ hitotsu | 6 | むっつ muttsu |
| 2 | ふたつ futatsu | 7 | ななつ nanatsu |
| 3 | みっつ mittsu | 8 | やっつ yattsu |
| 4 | よっつ yottsu | 9 | ここのつ kokonotsu |
| 5 | いつつ itsutsu | 10 | とお too |
When to use it: counting general objects with no obvious counter, ordering food (りんごをみっつください — "three apples, please"), and ages of small children. After 10, switch to Sino-Japanese numbers without a counter.
Why it matters: when in doubt about which counter to use, ～つ is always acceptable for inanimate objects. It is the beginner's escape hatch and even natives use it constantly.
What Are Counters and Why Do They Exist?
Japanese never counts nouns directly. You don't say "three books" — you say "books, three-volumes" (本を三冊). The counter (助数詞, josūshi) classifies the noun by shape, kind, or function — like English "three sheets of paper" or "two cups of coffee," but mandatory for everything.
Word order: [noun] を [number+counter] [verb]:
ビールを二本ください。 — "Two (bottles of) beer, please."
猫を三匹飼っています。 — "I have three cats."
The Essential Counters (90% of Daily Life)
| Counter | Used for | Example |
|---|---|---|
| つ | general objects (1–10) | りんご二つ |
| 人 (にん) | people | 学生が三人 |
| 本 (ほん) | long thin things: bottles, pens, umbrellas, trains, phone calls | ビール二本 |
| 枚 (まい) | flat things: paper, tickets, shirts, plates | 切符三枚 |
| 匹 (ひき) | small animals: cats, dogs, fish, insects | 犬一匹 |
| 頭 (とう) | large animals: horses, cows, elephants | 馬二頭 |
| 羽 (わ) | birds (and rabbits!) | 鳥三羽 |
| 冊 (さつ) | bound volumes: books, magazines | 本一冊 |
| 台 (だい) | machines & vehicles: cars, TVs, computers | 車一台 |
| 個 (こ) | small compact objects | 卵三個 |
| 杯 (はい) | cupfuls/bowlfuls | コーヒー一杯 |
| 回 (かい) | times/occurrences | 三回行った |
| 階 (かい/がい) | building floors | 五階 |
| 歳 (さい) | years of age | 二十歳* |
| 円 (えん) | yen | 百円 |
*二十歳 is read はたち — the most famous exception in the entire system.
Counter superstition watch: 本 counts long thin objects but also abstract "long" things — phone calls (電話一本), home runs, movies. Counters classify by conceptual shape, not just physical shape.
The Sound Changes: Three Rules, Not Three Hundred Exceptions
The reason "one bottle" is ippon, "three bottles" is sanbon, and "six bottles" is roppon is a regular sound process called renjō/onbin. Master these three rules:
Rule 1: いち, はち, じゅう + k/s/t/h-counter → doubled consonant (small っ)
| + 本 (hon) | + 回 (kai) | + 冊 (satsu) | |
|---|---|---|---|
| 1 いち | いっぽん ippon | いっかい ikkai | いっさつ issatsu |
| 8 はち | はっぽん happon | はっかい hakkai | はっさつ hassatsu |
| 10 じゅう | じゅっぽん juppon | じゅっかい jukkai | じゅっさつ jussatsu |
Rule 2: さん + h-counter → b-sound; ん forces voicing
さん ends in ん, which voices a following h → b: さん + ほん → さんぼん (sanbon), さん + はい → さんばい.
Rule 3: h-counters become p after っ
When rule 1 creates a small っ before an h-counter, h hardens to p: いっ + ほん → いっぽん, ろっ + ほん → ろっぽん.
The full 本 column (the model for all h-counters)
| Number | 本 | Pattern |
|---|---|---|
| 1 | いっぽん | っ + p |
| 2 | にほん | regular |
| 3 | さんぼん | ん + b |
| 4 | よんほん | regular |
| 5 | ごほん | regular |
| 6 | ろっぽん | っ + p |
| 7 | ななほん | regular |
| 8 | はっぽん | っ + p |
| 9 | きゅうほん | regular |
| 10 | じゅっぽん | っ + p |
Memorize the irregular slots — 1, 3, 6, 8, 10 — once, and they repeat across 匹 (いっぴき, さんびき, ろっぴき), 杯 (いっぱい, さんばい), 分 (いっぷん, さんぷん), and every other h-row counter. Same melody, different instrument.
人 (people): two true exceptions
| Number | Reading |
|---|---|
| 1 person | ひとり (native!) |
| 2 people | ふたり (native!) |
| 3 people | さんにん (regular from here) |
| 4 people | よにん (not よんにん) |
Dates: The Worst Offender
Days of the month mix native and Sino readings — days 1–10 plus a few others are native and must be memorized:
| Day | Reading | Day | Reading |
|---|---|---|---|
| 1st | ついたち | 7th | なのか |
| 2nd | ふつか | 8th | ようか |
| 3rd | みっか | 9th | ここのか |
| 4th | よっか | 10th | とおか |
| 5th | いつか | 14th | じゅうよっか |
| 6th | むいか | 20th | はつか |
| 24th | にじゅうよっか |
Everything else is regular: 11th = じゅういちにち, 25th = にじゅうごにち.
JLPT alert: ついたち (1st), はつか (20th), and ようか (8th) vs よっか (4th) appear on virtually every N5 listening test. The ようか/よっか distinction (8th vs 4th) is deliberately drilled because mishearing it changes appointments by four days.
Asking "How Many?": Question Words
| Question | Asks about | Example |
|---|---|---|
| いくつ | general objects / age | おいくつですか。(How old are you?) |
| 何人 (なんにん) | people | 何人家族ですか。 |
| 何本 (なんぼん) | long things — note the ん→b voicing! | ビールを何本飲みましたか。 |
| 何枚 (なんまい) | flat things | 切符を何枚買いますか。 |
| 何匹 (なんびき) | small animals | 猫を何匹飼っていますか。 |
| いくら | price | これはいくらですか。 |
何 (なん) behaves like さん for sound changes: 何本 = なんぼん, 何杯 = なんばい, 何匹 = なんびき.
Common Mistakes Learners Make
- Counting people with つ. ひとつ、ふたつ for people is wrong (and comically rude). People take 人: ひとり, ふたり, さんにん.
- Forgetting the word order. りんごを三つ食べた ✓ — the number+counter floats after the particle. 三つのりんごを食べた is grammatical but unnatural in conversation.
- Regularizing the irregulars. いちほん ✗, さんほん ✗, よんにん ✗ (for 4 people — it's よにん). The 1-3-6-8-10 melody must be drilled aloud, not just read.
- Reading 20歳 as にじゅっさい. It's はたち. (にじゅっさい is technically understood but 二十歳 in normal contexts reads はたち.)
- Using 匹 for big animals or 頭 for small ones. Rule of thumb: if you could pick it up, 匹; if it could carry you, 頭. Birds and (by famous historical quirk) rabbits take 羽.
- Avoiding counters entirely. Natives really do default to つ or 個 when unsure. Pick the right counter for the big twelve above, and fall back gracefully elsewhere — don't freeze.
Study Tips That Work
- Learn counters with example nouns, not definitions. Don't learn "枚 = flat objects"; learn シャツ一枚, 切符二枚, 紙三枚 as chunks.
- Drill the 1-3-6-8-10 melody aloud. いっぽん・さんぼん・ろっぽん・はっぽん・じゅっぽん, then transfer it: いっぴき・さんびき・ろっぴき… Your mouth learns the rule faster than your eyes.
- Count your real life. Pens on your desk (本), pages printed (枚), coffees today (杯), cats you saw (匹). One week of narrating real objects beats a month of flashcards.
- Master dates with a calendar. Each morning, say today's date aloud. The native-reading days (1st–10th, 14th, 20th, 24th) will cycle past you every month.
- Listen for counters. Shopping and restaurant dialogues in our N5 listening practice are saturated with counters and prices — the exact format the JLPT uses.
- Quiz yourself under time pressure. Counter sound-changes are a fixed feature of N5 and N4 vocabulary sections — drill them with the official JLPT sample questions or timed practice tests.
Quick-Reference Cheat Sheet
The escape hatch: unsure? Use つ (1–10) or 個 for objects. Never for people (人) or animals (匹).
The irregular slots: 1, 3, 6, 8, 10 — expect doubling (っ) on 1/6/8/10 and voicing (b/p) after ん on 3.
Must-memorize one-offs: ひとり (1 person), ふたり (2 people), よにん (4 people), はたち (20 years old), ついたち (1st), はつか (20th), よっか (4th) vs ようか (8th).
Fixed time readings: よじ (4:00), くじ (9:00), しがつ (April), しちがつ (July), くがつ (September).
Frequently Asked Questions
How many counters does Japanese actually have?
Around 350 exist, but everyday Japanese uses about 12–15, and even educated natives only actively use 30–40. The fifteen in this guide cover daily life and the JLPT through N3.
What happens if I use the wrong counter?
You'll be understood, and natives will rarely correct you. つ/個 for objects is always a safe fallback. The only genuinely jarring errors are counting people with つ or using no number word at all.
Why are rabbits counted like birds (羽)?
The popular explanation: Buddhist monks, forbidden from eating four-legged animals, classified rabbits as birds (long ears = wings, so the story goes) to keep them on the menu. Whatever the true origin, modern Japanese still counts rabbits with 羽.
Is it よん or し for 4? なな or しち for 7?
Default to よん and なな in almost all contexts. The exceptions are fixed expressions: しがつ (April), しちがつ (July), よじ (4 o'clock). When reading numbers aloud (phone numbers, prices), always よん/なな/きゅう for clarity.
Do I need counters for the JLPT?
Yes. N5 tests the core counters (つ, 人, 本, 枚, 匹, 歳, 円), dates, and time readings heavily — especially in listening. N4 and N3 add 冊, 台, 回, 階 and test the sound changes directly.
How do Japanese people count large numbers like millions?
By groups of 10,000 (万): 100万 = a million (lit. "100 ten-thousands"), 1億 = 100 million. Converting between English 1,000-grouping and Japanese 10,000-grouping is a genuine skill — practice by reading prices of cars and apartments.
Summary and Next Steps
Japanese counting = two number systems (Sino-Japanese for almost everything, native ひとつ・ふたつ as the universal fallback), a dozen everyday counters classified by shape, and three sound rules concentrated on the 1-3-6-8-10 slots. Add the memorized one-offs (ひとり, はたち, ついたち) and the system is yours.
Continue on NihongoDoya:
- See counters in sentences: Complete N5 Grammar Guide
- Learn the nouns to count: N5 Vocabulary List
- Drill dates and prices by ear: N5 Listening Practice