Time vocabulary in Japanese sits at the intersection of several numerical systems and a calendar tradition that layers East Asian astrology, Western scheduling, and Japan's imperial era names. For learners, the challenge is partly lexical (memorizing words) and partly systematic (understanding which reading of a numeral to use in a given context). Months use one set of number readings, days of the month use another, and the hours of the clock use a third. Mastering time expressions is therefore both a vocabulary exercise and a useful introduction to the coexistence of native (kun'yomi) and Sino-Japanese (on'yomi) number readings in the language.
This reference covers days of the week, months, days of the month, times of day, reading the clock, and relative time expressions such as "today", "tomorrow", "yesterday", "this week", and "next year". It also introduces the Japanese era-name system (年号, nengou) that runs in parallel with the Gregorian calendar in official contexts. Cultural notes explain the etymological background of day names and the significance of certain numbers in Japanese scheduling culture.
Readings are given in hiragana and romaji. Kanji appear alongside where they are standard, which is in most contexts outside early-childhood materials.
Days of the Week
The seven weekday names in Japanese follow the astrological seven-day week transmitted from the Hellenistic world through China. Each day is associated with one of the "seven luminaries" (七曜, shichi you): the sun, the moon, and the five classical planets visible to the naked eye. The word 曜日 (youbi) means "luminary day" and is suffixed to each day name.
| Japanese | Romaji | English | Association |
|---|---|---|---|
| 月曜日 | getsuyoubi | Monday | Moon (月) |
| 火曜日 | kayoubi | Tuesday | Fire / Mars (火) |
| 水曜日 | suiyoubi | Wednesday | Water / Mercury (水) |
| 木曜日 | mokuyoubi | Thursday | Wood / Jupiter (木) |
| 金曜日 | kin'youbi | Friday | Gold / Venus (金) |
| 土曜日 | doyoubi | Saturday | Earth / Saturn (土) |
| 日曜日 | nichiyoubi | Sunday | Sun (日) |
Etymology note: The same planetary associations appear in Romance languages (French lundi for Moon-day, mardi for Mars-day) because they share the astrological origin. Germanic languages replaced the planets with their own deities (Tuesday for Tiw, Thursday for Thor), which broke the pattern in English.
Common expressions:
- 今日は何曜日ですか (kyou wa nan youbi desu ka) - what day is it today
- 毎週月曜日 (maishuu getsuyoubi) - every Monday
- 土日 (donichi) - weekend (literally "Saturday and Sunday")
- 平日 (heijitsu) - weekdays
- 週末 (shuumatsu) - weekend (formal)
Months of the Year
Japanese month names are formed by combining the number (1 through 12) with 月 (gatsu), which means "month". All twelve months use the on'yomi reading of the numeral. Three months have slightly irregular readings.
| Japanese | Romaji | English |
|---|---|---|
| 一月 | ichigatsu | January |
| 二月 | nigatsu | February |
| 三月 | sangatsu | March |
| 四月 | shigatsu | April |
| 五月 | gogatsu | May |
| 六月 | rokugatsu | June |
| 七月 | shichigatsu | July |
| 八月 | hachigatsu | August |
| 九月 | kugatsu | September |
| 十月 | juugatsu | October |
| 十一月 | juuichigatsu | November |
| 十二月 | juunigatsu | December |
The irregular readings are:
- 四月 uses "shi" (not "yon") for 4
- 七月 uses "shichi" (not "nana") for 7
- 九月 uses "ku" (not "kyuu") for 9
These readings are fixed and cannot be substituted. Saying よんがつ for April sounds childish or foreign.
Cultural note: The number four (四) shares its sound "shi" with the word for death (死). Hospitals sometimes skip floor 4 or room 404 the way some Western buildings skip 13. In spoken counting, "yon" is often preferred over "shi" to avoid the association, but month names remain fixed.
Each month also has a traditional poetic name preserved in literature and calendars:
| Month | Traditional Name | Meaning |
|---|---|---|
| 1 | 睦月 (mutsuki) | month of affection |
| 2 | 如月 (kisaragi) | changing clothes |
| 3 | 弥生 (yayoi) | new life |
| 4 | 卯月 (uzuki) | deutzia flower |
| 5 | 皐月 (satsuki) | rice planting |
| 6 | 水無月 (minazuki) | no-water month |
| 7 | 文月 (fumizuki) | letter month |
| 8 | 葉月 (hazuki) | leaf month |
| 9 | 長月 (nagatsuki) | long month |
| 10 | 神無月 (kannazuki) | no-god month |
| 11 | 霜月 (shimotsuki) | frost month |
| 12 | 師走 (shiwasu) | priests running |
These names appear on traditional calendars, in tea ceremony, and in modern baby names (e.g., 弥生 as a girl's name).
Days of the Month
Unlike months, day-of-month readings are largely irregular and use the older native (kun'yomi) numerals for the first ten days, then shift to on'yomi for the rest, with scattered exceptions.
| Day | Japanese | Romaji |
|---|---|---|
| 1 | 一日 | tsuitachi |
| 2 | 二日 | futsuka |
| 3 | 三日 | mikka |
| 4 | 四日 | yokka |
| 5 | 五日 | itsuka |
| 6 | 六日 | muika |
| 7 | 七日 | nanoka |
| 8 | 八日 | youka |
| 9 | 九日 | kokonoka |
| 10 | 十日 | tooka |
| 11 | 十一日 | juuichinichi |
| 12 | 十二日 | juuninichi |
| 14 | 十四日 | juuyokka |
| 17 | 十七日 | juushichinichi |
| 19 | 十九日 | juukunichi |
| 20 | 二十日 | hatsuka |
| 24 | 二十四日 | nijuuyokka |
| 29 | 二十九日 | nijuukunichi |
| 30 | 三十日 | sanjuunichi |
| 31 | 三十一日 | sanjuuichinichi |
The first day of the month is called 一日 (tsuitachi), a word derived from 月立ち (tsukitachi, "month standing"). The 20th is 二十日 (hatsuka), also from a native reading. Days 14, 24, and 20 preserve native readings into the second half of the month.
Learning tip: Days 1 through 10, plus 14, 20, and 24, should be memorized as units. Once those are secured, the rest of the month follows predictable on'yomi + 日 patterns.
Times of Day
| Japanese | Romaji | English |
|---|---|---|
| 朝 | asa | morning |
| 昼 | hiru | noon / daytime |
| 午前 | gozen | AM / before noon |
| 午後 | gogo | PM / after noon |
| 夕方 | yuugata | early evening |
| 夜 | yoru | night |
| 晩 | ban | evening |
| 深夜 | shin'ya | late night |
| 真夜中 | mayonaka | midnight |
| 早朝 | souchou | early morning |
| 正午 | shougo | noon (exact) |
Reading the Clock
Hours and minutes in Japanese combine a number with 時 (ji, hour) and 分 (fun / pun, minute). A long list of irregular readings applies.
| Hour | Japanese | Romaji |
|---|---|---|
| 1:00 | 一時 | ichiji |
| 2:00 | 二時 | niji |
| 3:00 | 三時 | sanji |
| 4:00 | 四時 | yoji |
| 5:00 | 五時 | goji |
| 6:00 | 六時 | rokuji |
| 7:00 | 七時 | shichiji |
| 8:00 | 八時 | hachiji |
| 9:00 | 九時 | kuji |
| 10:00 | 十時 | juuji |
| 11:00 | 十一時 | juuichiji |
| 12:00 | 十二時 | juuniji |
Important irregularities:
- 4:00 is 四時 (yoji), not "shiji"
- 7:00 is 七時 (shichiji), not "nanaji"
- 9:00 is 九時 (kuji), not "kyuuji"
For minutes, the reading ふん (fun) alternates with ぷん (pun) depending on the preceding number:
| Minutes | Japanese | Romaji |
|---|---|---|
| 1 | 一分 | ippun |
| 2 | 二分 | nifun |
| 3 | 三分 | sanpun |
| 4 | 四分 | yonpun |
| 5 | 五分 | gofun |
| 6 | 六分 | roppun |
| 7 | 七分 | nanafun |
| 8 | 八分 | happun or hachifun |
| 9 | 九分 | kyuufun |
| 10 | 十分 | juppun or jippun |
| 15 | 十五分 | juugofun |
| 30 | 三十分 or 半 | sanjuppun / han |
Example times:
- 3:15 - 三時十五分 (sanji juugofun)
- 7:30 - 七時半 (shichiji han) or 七時三十分 (shichiji sanjuppun)
- 9:45 AM - 午前九時四十五分 (gozen kuji yonjuugofun)
Asking and answering time:
- 今何時ですか (ima nanji desu ka) - what time is it now
- 午後三時半です (gogo sanji han desu) - it is 3:30 PM
Relative Time Words
| Japanese | Romaji | English |
|---|---|---|
| 今 | ima | now |
| 今日 | kyou | today |
| 昨日 | kinou | yesterday |
| 明日 | ashita / asu | tomorrow |
| 明後日 | asatte | the day after tomorrow |
| 一昨日 | ototoi | the day before yesterday |
| 毎日 | mainichi | every day |
| 今週 | konshuu | this week |
| 先週 | senshuu | last week |
| 来週 | raishuu | next week |
| 再来週 | saraishuu | the week after next |
| 毎週 | maishuu | every week |
| 今月 | kongetsu | this month |
| 先月 | sengetsu | last month |
| 来月 | raigetsu | next month |
| 再来月 | saraigetsu | the month after next |
| 今年 | kotoshi | this year |
| 去年 | kyonen | last year |
| 来年 | rainen | next year |
| 再来年 | sarainen | the year after next |
| 毎年 | maitoshi / mainen | every year |
The prefixes form predictable patterns: 先 (sen) for "last", 今 (kon) for "this", 来 (rai) for "next", 再来 (sarai) for "the one after next".
Duration and Frequency
| Japanese | Romaji | English |
|---|---|---|
| 一時間 | ichi jikan | one hour (duration) |
| 二時間 | ni jikan | two hours |
| 半日 | hannichi | half a day |
| 一日 | ichi nichi | one day (duration) |
| 一週間 | isshuukan | one week |
| 一ヶ月 | ikkagetsu | one month |
| 一年間 | ichi nen kan | one year |
| いつも | itsumo | always |
| よく | yoku | often |
| 時々 | tokidoki | sometimes |
| たまに | tama ni | occasionally |
| 全然 | zenzen | not at all |
The word 間 (kan) is appended to mark a duration: 一週間 (isshuukan, for one week) versus 来週 (raishuu, next week).
Era Names (Nengou)
Japan officially uses imperial era names in parallel with the Gregorian calendar. Five major eras since the 1868 modernization:
| Era | Japanese | Dates | Corresponding Western |
|---|---|---|---|
| Meiji | 明治 | 1868 - 1912 | |
| Taisho | 大正 | 1912 - 1926 | |
| Showa | 昭和 | 1926 - 1989 | |
| Heisei | 平成 | 1989 - 2019 | |
| Reiwa | 令和 | 2019 - present |
Conversions:
- Showa year + 25 = Western year minus 1900 (e.g., Showa 50 = 1975)
- Heisei year + 1988 = Western year (e.g., Heisei 10 = 1998)
- Reiwa year + 2018 = Western year (e.g., Reiwa 6 = 2024)
Nengou dates appear on coins, driver's licenses, tax forms, and government correspondence. A ten-thousand-yen bill printed in Reiwa 2 is dated 令和二年.
Common Mistakes
- Saying "yongatsu" for April. The correct form is 四月 shigatsu.
- Using "kyuuji" for 9:00. The correct form is 九時 kuji.
- Confusing 半 (han) with 半分 (hanbun). 半 is used specifically in time expressions (三時半, 3:30). 半分 means "half" in general contexts.
- Reading 一日 as "ichinichi" when it means the first of the month. The first is 一日 (tsuitachi); "ichi nichi" is the duration "one day".
- Confusing 明後日 (asatte, day after tomorrow) with 明日 (ashita, tomorrow).
- Using 来月 when the speaker means "next Monday". 来月 means next month; for next Monday, say 来週の月曜日 (raishuu no getsuyoubi).
Quick Reference
- What day is it: 今日は何曜日ですか (kyou wa nan youbi desu ka)
- What time is it: 今何時ですか (ima nanji desu ka)
- Today / tomorrow / yesterday: 今日 / 明日 / 昨日
- Last week / this week / next week: 先週 / 今週 / 来週
- January to December: 一月 - 十二月 (ichigatsu - juunigatsu)
- The 1st of the month: 一日 (tsuitachi)
- 3:30: 三時半 (sanji han)
- AM / PM: 午前 / 午後 (gozen / gogo)
- Every day: 毎日 (mainichi)
- Weekend: 週末 (shuumatsu)
See Also
- Japanese Counting: Numbers and Counters Guide
- Japanese Counters and Classifiers
- Japanese Common Phrases: Daily Conversation Reference
- Japanese Kanji: Stroke Order, Radicals, Reading
- Hiragana Complete Guide
- Katakana Complete Guide
- Japanese Verb Conjugation: Beginner's Guide
Frequently Asked Questions
Why are Japanese days of the week named after planets?
Japanese day names follow the seven-day astrological week, a system that originated in Babylonian and Hellenistic astrology and was transmitted to Japan via China. Each day is named for one of five classical planets plus the sun and moon: 月 moon, 火 fire/Mars, 水 water/Mercury, 木 wood/Jupiter, 金 gold/Venus, 土 earth/Saturn, 日 sun.
How do I say months in Japanese?
Months are formed by combining the number with 月 (gatsu): 一月 (ichigatsu) January, 二月 (nigatsu) February, and so on through 十二月 (juunigatsu) December. Note the irregular reading 四月 (shigatsu) with 'shi' rather than 'yon', and 七月 (shichigatsu) and 九月 (kugatsu). The word for 'April' (shigatsu) shares sound with 'death', which is why many hospitals avoid room numbers with four.
What is the difference between 今日, 明日, and 昨日?
今日 (kyou) means today, 明日 (ashita) means tomorrow, and 昨日 (kinou) means yesterday. Extended time words include 明後日 (asatte) for the day after tomorrow, 一昨日 (ototoi) for the day before yesterday, and 毎日 (mainichi) for every day.
How is time read in Japanese?
Hours use 時 (ji) and minutes use 分 (fun/pun). 3:15 is 三時十五分 (sanji juugofun). Half past is 半 (han), so 3:30 can be said as 三時半 (sanji han). AM and PM are marked with 午前 (gozen) before the hour and 午後 (gogo) after. The 24-hour clock is common in schedules and printed timetables.
Why does 四月 use 'shi' instead of 'yon'?
Month names use the older on'yomi (Chinese-derived) reading of each numeral. 四 in this context is read 'shi'. Day numbers (四日 yokka, 'the fourth') use the native Japanese reading. This split between kun and on readings in dates is one of the more irregular corners of Japanese numeric language.
How do I say 'every Monday' or 'every week'?
Use the prefix 毎 (mai): 毎週 (maishuu) every week, 毎月 (maitsuki) every month, 毎年 (maitoshi) every year. For specific days: 毎週月曜日 (maishuu getsuyoubi) every Monday. For habitual actions, 毎日 (mainichi) means every day.
What is the Japanese era name system and is it still used?
Japan officially uses its imperial era names (年号, nengou) alongside the Western calendar. The current era is Reiwa (令和), which began in May 2019. Dates on government forms, coins, newspapers, and driver's licenses use era year plus month and day. 2024 corresponds to Reiwa 6. The Gregorian system is equally common in daily life.
