The basic word for day in Japanese is 日（ひ, hi）, but the reading and expression change with the meaning. 一日（いちにち, ichinichi） means one day, while 昼（ひる, hiru） refers to daytime or noon in suitable contexts. The character 日 also appears in dates and words such as 毎日（まいにち）, “every day.”
日（ひ） = a day; 一日（いちにち） = one day; 昼（ひる） = daytime / noon. Say 今日は何曜日ですか for “What day of the week is it today?” and 今日は何日ですか for “What is today’s date?”
- How Do You Say Day in Japanese?
- Different Japanese Words for Day
- Day in Japanese: Quick Comparison
- How to Read 日 in Different Expressions
- Today, Tomorrow, and Yesterday
- Day of the Week Versus Calendar Date
- Useful Expressions with Day
- Example Sentences Using Day in Japanese
- Frequently Asked Questions About Day in Japanese
- Summary: How to Say Day in Japanese
How Do You Say Day in Japanese?
日（ひ） is a basic noun for a day. その日（そのひ） means “that day,” and いい日（いいひ） means “a good day.” The character can also relate to the sun, so context determines the intended meaning.
English “day” can describe a twenty-four-hour period, a date, the light part of the day, or a particular occasion. Japanese uses different words and readings for these ideas. Learn a complete expression rather than assigning the reading hi to every occurrence of 日.
Example: その日（そのひ）— that day
Different Japanese Words for Day
The following forms are useful starting points. They overlap in English translation, but they answer different questions: which day, how long, what part of the day, or how often?
1. 日（ひ）— A Day
Use ひ in phrases such as 次の日（つぎのひ）, “the next day,” and 休みの日（やすみのひ）, “a day off.” These expressions identify a day as an occasion or part of a sequence.
その日は忙しいです means “I am busy that day.” The phrase その日 names the day under discussion. It does not give a duration or the calendar number by itself.
2. 一日（いちにち）— One Day
いちにち is a day as a period or quantity. 一日休みます can mean “I will take a day off.” 一日中（いちにちじゅう） means “all day.”
The same written characters 一日 have a different reading when they mean the first day of a month: ついたち. A duration of one day and the calendar date “the first” are different uses, even though the kanji look identical.
3. 昼（ひる）— Daytime / Noon
昼 refers to the daytime, particularly the middle part of the day, and can mean noon in appropriate expressions. 昼間（ひるま） is a useful word for daytime as opposed to night.
昼は働いています means “I work during the day,” in a suitable context. The sentence concerns the daytime part of a routine, not a duration of one complete day.
4. 毎日（まいにち）— Every Day
毎日 means “every day.” 毎日日本語を勉強します means “I study Japanese every day.” The reading is mainichi, not a combination you can produce by reading 日 as hi.
For a daily habit, 毎日 gives the frequency. It does not mean that the action continues for the whole day. Studying every day may involve a short session on each day rather than studying all day long.
Day in Japanese: Quick Comparison
← Swipe horizontally to see the full table →
| Japanese | Reading | Meaning |
|---|---|---|
| 日 | ひ — hi | a day, in expressions such as that day |
| 一日 | いちにち — ichinichi | one day / a day as a period |
| 一日 | ついたち — tsuitachi | the first day of a month |
| 昼 | ひる — hiru | daytime / noon |
| 昼間 | ひるま — hiruma | daytime |
| 毎日 | まいにち — mainichi | every day |
| 一日中 | いちにちじゅう — ichinichijū | all day |
| 曜日 | ようび — yōbi | day of the week |
The table highlights two different distinctions. Mainichi tells you frequency, while ichinichijū tells you duration across a day. Yōbi identifies the Japanese day of the week, while a date expression gives the day’s number in a month.
How to Read 日 in Different Expressions
Japanese kanji can have more than one reading. 日 is read ひ in その日, にち in 毎日, and as part of the special reading きょう in 今日. The surrounding word determines the reading.
Hi is a short syllable. Ichinichi can be practiced as i-chi-ni-chi, keeping the vowels clear. In yōbi, the first vowel is long; the hiragana is ようび.
Do not try to infer every date reading from an isolated character. Calendar expressions contain several special forms. Listen to whole words such as kyō, ashita, and tsuitachi instead of translating the kanji one character at a time.
Today, Tomorrow, and Yesterday
今日（きょう, kyō） means “today.” 明日（あした, ashita） means “tomorrow,” and 昨日（きのう, kinō） means “yesterday.” These are useful everyday words with readings that should be learned as complete vocabulary.
- 今日（きょう） — today
- 明日（あした） — tomorrow
- 昨日（きのう） — yesterday
- 明後日（あさって） — the day after tomorrow
- 一昨日（おととい） — the day before yesterday
For example, 明日は休みです means “Tomorrow is a day off.” The topic marker は is pronounced wa. The expression does not need the ordinary noun hi because ashita already identifies the day.
Some of these words have additional readings in formal or other contexts. Begin with the everyday forms shown here, then learn alternatives when you encounter them in a complete sentence.
Day of the Week Versus Calendar Date
今日は何曜日ですか asks “What day of the week is it today?” An answer might be 月曜日です, “It is Monday.” The word 曜日 concerns the weekly cycle.
今日は何日ですか asks for the date within the month. 何日 is read なんにち in this question. An answer gives a date such as 十五日（じゅうごにち）, “the fifteenth.”
The first day is tsuitachi, and several other dates have special readings, such as 二日（ふつか） and 三日（みっか）. Do not assume every calendar date is the basic number followed by a mechanically identical ending.
Useful Expressions with Day
休みの日 is a day off. 仕事の日（しごとのひ） is a workday in a suitable phrase. 平日（へいじつ） usually refers to weekdays or ordinary working days, in contrast with weekends or holidays in the relevant context.
For “Have a nice day,” 良い一日を（よいいちにちを） is an understandable well-wishing expression. It is not necessary to use it as a fixed farewell in every Japanese conversation; choose a phrase that fits the situation.
いい日でした means “It was a good day.” 今日はいい日です means “Today is a good day.” These model sentences help distinguish hi as a noun from an expression that directly identifies today.
Example Sentences Using Day in Japanese
I study Japanese every day.
Use: Expressing how often you study.
What day of the week is it today?
Use: Asking about the weekday rather than the date.
Tomorrow is a day off.
Use: Talking about the next day with an everyday relative-time word.
Frequently Asked Questions About Day in Japanese
Tap a question below to see the answer.
What is day in Japanese?
The basic noun is 日（ひ）. Other common forms include 一日（いちにち） for one day and 昼（ひる） for daytime.
What is the difference between hi and nichi?
They are different readings of 日 used in different words and constructions. Learn complete expressions such as その日（そのひ） and 毎日（まいにち）.
Does 一日 mean ichinichi or tsuitachi?
For a one-day period, it is normally いちにち. For the first day of a month, it is ついたち.
How do you say every day?
Say 毎日（まいにち）. It expresses frequency, not necessarily an action lasting all day.
How do you ask what day of the week it is?
Say 今日は何曜日ですか, read きょうはなんようびですか.
How do you ask for today’s date?
Say 今日は何日ですか, read きょうはなんにちですか. This asks for the day’s number in the month.
Summary: How to Say Day in Japanese
Day in Japanese can be 日（ひ）, 一日（いちにち）, or 昼（ひる）, depending on the meaning. Learn 日 inside complete expressions because its reading changes from word to word.
Useful forms include 毎日, “every day,” 今日, “today,” and 曜日, “day of the week.” Distinguish a weekday question from a calendar-date question, and practice each with its complete Japanese reading.
