Japanese counter words (助数詞, josūshi) are obligatory classifiers attached to numbers when counting. The choice depends on the shape, type, or category of the thing being counted — long thin objects take 本, flat objects take 枚, small animals take 匹, machines take 台, and people take 人. This reference lets you search 60+ common counters by what they count.
How it works
Each entry pairs a counter with the category it covers, its reading, and an example. The tricky part of counters is the euphonic sound change after certain numbers, which the examples capture:
本 (hon, long thin objects): 1 いっぽん ippon, 3 さんぼん sanbon,
6 ろっぽん roppon, 8 はっぽん happon, 10 じゅっぽん juppon
人 (nin, people): 1 ひとり hitori, 2 ふたり futari, 3+ regular さんにん
匹 (hiki, small animals): 1 いっぴき ippiki, 3 さんびき sanbiki, 6 ろっぴき roppikiSearch matches against the counter kanji, its romaji reading, and the English category, so you can look up either direction.
The most common counters at a glance
Learning the high-frequency counters covers the vast majority of everyday situations. A practical shortlist:
| Counter | Reading | Counts |
|---|---|---|
| 本 | hon | Long thin objects: pens, bottles, bananas, roads |
| 枚 | mai | Flat thin objects: sheets, tickets, plates, T-shirts |
| 台 | dai | Machines and vehicles: cars, computers, TVs |
| 匹 | hiki | Small and medium animals: cats, fish, insects |
| 頭 | tou | Large animals: cows, horses, elephants |
| 羽 | wa | Birds and rabbits |
| 冊 | satsu | Bound volumes: books, notebooks, magazines |
| 杯 | hai | Cups, glasses, bowls of food or drink |
| 階 | kai | Floors of a building |
| 回 | kai | Number of times (occurrences) |
| 人 | nin | People (with irregular 1 = hitori, 2 = futari) |
| 個 | ko | Small compact objects: apples, stones, eggs |
Why the reading changes with the number
The sound changes — called 連濁 (rendaku) and 促音 (gemination) — are phonological rules that Japanese applied consistently across counters. With 本, for example, the initial h weakens to b after 3 (sanbon), doubles to pp after 1, 6, 8, and 10 (ippon, roppon), and stays unchanged after 2, 4, 5, 7, 9. The pattern is the same for 匹 (hiki → ippiki / sanbiki / roppiki) and 杯 (hai → ippai / sambai / roppai). Noticing this pattern means you learn the rule once rather than memorising each number combination separately.
Practical examples and fallback
To count three pencils: 鉛筆三本 (enpitsu sanbon). Two cats: 猫二匹 (neko nihiki). Five cars: 車五台 (kuruma godai). When you genuinely do not know the right counter for an inanimate object, the native Japanese つ counter (一つ, 二つ … 十 for ten and above, then switch to 個) is a polite and universally understood fallback. It sounds slightly informal but never wrong. This reference focuses on the irregular forms that learners most need to get right.