Numbers, counters, time and dates

Four numbers have two readings. Zero is ゼロ (zero) or れい (rei). For 4, 7 and 9, よん (yon), なな (nana) and きゅう (kyū) are the usual ones when you count or say a number on its own. し (shi), しち (shichi) and く (ku) turn up in fixed places, such as 四月 (shigatsu, April), 七時 (shichiji, seven o'clock) and 九時 (kuji, nine o'clock).

From 11 to 99, numbers are built like a sum: 11 is “ten one”, 十一 (jūichi); 20 is “two ten”, 二十 (nijū); 99 is 九十九 (kyūjūkyū). In everyday life most numbers are written in Arabic digits; kanji numbers are used in vertical text and in some words and names.

百 (hyaku) is 100 and 千 (sen) is 1,000. You don't say “one” before them. Some combinations change their sound: 300 is 三百 (sanbyaku), 600 六百 (roppyaku), 800 八百 (happyaku), 3,000 三千 (sanzen) and 8,000 八千 (hassen).

Big numbers are grouped by four digits, not three. 万 (man) is 10,000, so 100,000 is 十万 (jūman, “ten ten-thousands”) and one million is 百万 (hyakuman). The next step is 億 (oku), 100 million. Unlike 百 and 千, 万 needs the one: 一万 (ichiman).

Prices are usually written in digits followed by 円 (en, yen): 1,500円 is read 千五百円 (sen gohyakuen). Watch 四円 (yoen, 4 yen). Rents and salaries are counted in 万: 八万円 (hachiman'en, 80,000 yen).

When you count things, Japanese adds a counter to the number, chosen by the kind of thing, a bit like “two cups of tea” or “three sheets of paper” in English. ～つ (-tsu) is the general counter for things up to ten; after ten you just use the number.

The number and counter usually come after the noun and its particle, just before the verb: りんごを三つください (ringo o mittsu kudasai, three apples, please), ビールを二本お願いします (bīru o nihon onegai shimasu, two bottles of beer, please).

Before counters starting with k, s, t or h, the numbers 1, 8 and 10 (and 6 before k and h) often shorten and double the consonant (いっこ, ikko), and h may turn into p or b (いっぽん, ippon; さんぼん, sanbon).

Here are four counters all the way to ten, so you can see the sound changes. People have their own words for one and two, ひとり (hitori) and ふたり (futari), and four people is よにん (yonin). Age 20 has a special word too: はたち (hatachi), usually written 二十歳. Where two forms are given, both are used.

Hours take ～時 (-ji) and minutes take ～分 (-fun or -pun). Four o'clock is よじ (yoji), seven o'clock しちじ (shichiji) and nine o'clock くじ (kuji). 半 (han) means half past: 三時半 (sanji han, half past three). 午前 (gozen, a.m.) and 午後 (gogo, p.m.) go before the time: 午後二時 (gogo niji, 2 p.m.).

The same words give lengths of time, with ～時間 (-jikan) for hours: 二時間 (nijikan, two hours), 三十分 (sanjuppun, thirty minutes). Timetables use the 24-hour clock, and so do many announcements: 十八時 (jūhachiji, 18:00).

Months are simply the number + 月 (gatsu): 一月 (ichigatsu, January) to 十二月 (jūnigatsu, December). Watch 四月 (shigatsu), 七月 (shichigatsu) and 九月 (kugatsu). The days of the week are 月曜日 (getsuyōbi, Monday), 火曜日 (kayōbi), 水曜日 (suiyōbi), 木曜日 (mokuyōbi), 金曜日 (kin'yōbi), 土曜日 (doyōbi) and 日曜日 (nichiyōbi, Sunday).

Dates go from big to small: year, month, day. 26 September 2026 is written 2026年9月26日. Most days are the number + 日 (nichi), but the first ten, the 14th, the 20th and the 24th have special readings. The same words (except the 1st) also mean a number of days: 三日 (mikka) is the 3rd or three days.