Months in Japanese

In Japanese, months don't have names like January, February, etc., the way we have in English. Instead, February, the second month, for example, is referred to as "month two," ni-gatsu 二月. Its number may also be spelled with an Arabic numeral instead of kanji, as ２月.

Month Name	In Japanese	romaji	Translation
January	一月（いちがつ） or １月	ichigatsu	Month one.
February	二月（にがつ） or ２月	nigatsu	Month two.
March	三月（さんがつ） or ３月	sangatsu	Month three.
April	四月（しがつ） or ４月	shigatsu	Month four.
May	五月（ごがつ） or ５月	gogatsu	Month five.
June	六月（ろくがつ） or ６月	rokugatsu	Month six.
July	七月（しちがつ） or ７月	shichigatsu	Month seven.
August	八月（はちがつ） or ８月	hachigatu	Month eight.
September	九月（くがつ） or ９月	kugatsu	Month nine.
October	十月（じゅうがつ） or １０月	juugatsu	Month ten.
November	十一月（じゅういちがつ） or １１月	juuichigatsu	Month eleven.
December	十二月（じゅうにがつ） or １２月	juunigatsu	Month twelve.

Likewise, the name of the anime 3-Gatsu no Lion ３月のライオン means literally "The Lion of March."

• Counting Months
  • Counting Moons
• Asking Questions

Counting Months

The words ichigatsu, nigatsu, etc., are only used to refer to a month on the calendar, such as "month number two." In order to say "two months," as in a length of time—e.g. "it takes two months to do this"—we use ~kagetsu ～ヶ月 instead, which is a counter for months.

Time length	In Japanese	romaji
One month	一ヶ月（いっかげつ） or １ヶ月	ikkagetsu
Two months	二ヶ月（にかげつ） or ２ヶ月	nikagetsu
Three months	三ヶ月（さんかげつ） or ３ヶ月	sankagetsu
Four months	四ヶ月（しかげつ） or ４ヶ月	yonkagetsu
Five months	五ヶ月（ごかげつ） or ５ヶ月	gokagetsu
Six months	六ヶ月（ろっかげつ） or ６ヶ月	rokkagetsu
Seven months	七ヶ月（ななかげつ） or ７ヶ月	nanakagetsu
Eight months	八ヶ月（はちかげつ） or ８ヶ月	hachikagetsu
Nine months	九ヶ月（きゅうかげつ） or ９ヶ月	kyuugatsu
Ten months	十ヶ月（じゅっかげつ） or １０ヶ月	jukkagetsu
Eleven months	十一ヶ月（じゅういっかげつ） or １１ヶ月	juuikkagetsu
Twelve months	十二ヶ月（じゅうにかげつ） or １２ヶ月	juunikagetsu

This counter is mixed with others like this:

• ikkagetsu isshuukan
  一ヶ月一週間
  One month and one week long.
• ichinen ikkagetsu
  一年一ヶ月
  One year and one month long.

Referring to halves:

• hankagetsu
  半ヶ月
  Half month.
• ikkagetsu-han
  一ヶ月半
  One month and half.

Since it's a counter, it can be used with the mo も particle to say stuff like this:

• ikkagetsu mo kakarimasen yo
  一ヶ月もかかりませんよ
  It won't take even one month. (it will be really quick.)
• ikkagetsu mo kakarimashita yo
  一ヶ月もかかりましたよ
  It took even one month. (a whole month just for this, it was really slow.)

There's a few things to take note of.

First off, notice that the 月 kanji is read as gatsu がつ when saying "January," but getsu げつ when saying "one month." These are two different readings of the same kanji. When saying calendar months, it's gatsu, when counting lengths of time, it's getsu.

Some numbers also have multiple readings: four (四) can be shi し or yon よん, seven (七) can be shichi しち or nana なな, and nine (九) can be ku く or kyuu きゅう.

Since shi and shichi sound similar, sometimes yongatsu よんがつ and nanagatsu なながつ are used instead to disambiguate.

Source: japanesewithanime.com (CC BY-SA 4.0)

In a few words, there's a change of pronunciation at morpheme boundary that merges the number with the counter morpheme: ichi-ka-getsu いちかげつ becomes ikkagetsu いっかげつ, and so on.

This change is called sokuonbin 促音便, which adds a sokuon, a geminate consonant, represented by the small tsu っ.

Some words that feature sokuonbin always feature it, e.g. you don't say roku-ka-getsu ろくかげつ, you always say rokkagetsu ろっかげつ. Others can be pronounced either way, like hachikagetsu はちかげつ and hakkagetsu はっかげつ.

A weird one is jukkagetsu じゅっかげつ, the one for "ten months," because normally a juu syllable doesn't result in sokuonbin. However, a similar thing occurs in "ten minutes" being pronounced juppun 十分（じゅっぷん).

The small ke ヶ between the number and the 月 kanji is an abbreviated way to write ka 箇. It comes from the take 竹, "bamboo," component at the top of that kanji that looks like a ke ケ.

Source: japanesewithanime.com (CC BY-SA 4.0)

It's possible to spell all the words for counting months with this kanji instead of the small ke ヶ, e.g.: ikkagetsu 一箇月, nikagetsu 二箇月, etc.: 三箇月, 四箇月, 五箇月, 六箇月, 七箇月, 八箇月, 九箇月, 十箇月, 十一箇月, 十二箇月.

Counting Moons

The kanji for "month," getsu 月, is also the kanji for "moon," tsuki 月. Moons and months are kind of related, as it takes around one month for a moon to cycle from new moon, to full moon, to back to new moon.

These are different words spelled with the same kanji. The tsuki reading is kun'yomi 訓読み, while getsu is on'yomi 音読み.

It's possible to count moons, which in effect means you're counting months, but in this case you'll use the kun'yomi readings of the numbers, like in hitotsu 一つ, futatsu 二つ, mittsu 三つ, as opposed to the on'yomi ichi, ni, san.

• hitotsuki
  一月
  One moon = one month.
• futatsuki
  二月
  Two moons = two months.
• mitsuki
  三月
  Three moons = three months.

Confusingly, hitotsuki 一月, "one moon," is spelled the same way as ichigatsu 一月, "January," but the former is a length of time of one month, while the latter is the month in the calendar.

Generally the word will be ichigatsu, not hitotsuki. When it's hitotsuki, it will probably have furigana to disambiguate, e.g. ichigatsu will be written simply as 一月, while hitotsuki will be written 一月（ひとつき）.

Also be warned that some words related to moon use the getsu reading and have nothing to do with months, e.g. shingetsu 新月, "new moon."

See Moon Phases in Japanese for details.

Asking Questions

To ask "what month" or "how many months" in Japanese, you use the interrogative nan~ 何～ morpheme instead of a number with the words we've seen before. For example:

• nangatsu?
  何月？
  What month?
  • This expects an answer like ichigatsu 一月, "month one," "January."
• nankagetsu?
  何ヶ月？
  How many months?
  • This expects an answer like ikkagetsu 一ヶ月, "one month."

Note that in the answers a number like ichi 一 will replace the interrogative nan~ 何～, as it's the focus of the sentence.

• anata wa nangatsu ni umareta?
  あなたは何月に生まれた？
  In what month were [you] born?
  • umu 生む - "to birth."
  • umareru 生まれる - "to be birthed," passive form of umu. "To be born."
• watashi wa shichigatsu ni umareta
  私は七月に生まれた
  I was born in the month seven (July).
  • Note: when talking about months in gestation, the counter is ~kagetsu instead, since you're talking about how many months were you in gestation, and not the month in the calendar.
  • watashi wa nanakagetsu de umareta
    私は7ヶ月で生まれた
    I was born in seven months.
  • The de で particle is used here because "in" means "it took" seven months for it to happen.
• sore wa {nankagetsu φ kakaru}?
  それは何ヶ月かかる？
  That {will take how many months}?
  How many months will that take?
  (double subject construction.)
  • kakaru - "to take" a resource, like time or money. To cost.
• sankagetsu
  三ヶ月
  Three months.
• sankagetsu φ kakaru
  三ヶ月かかる
  [It] will take three months.