Months in Japanese: Modern Names, Old Names and Date Readings

Japanese months don't have names. They have numbers. January is 一月, "month one", and December is 十二月, "month twelve". If you can count to twelve, you can already write all of them.

Saying them is nearly as easy. Three months use a reading you might not expect, and then the days of the month bring in a set of old native words that have to be memorized. Those days are where most of the work is.

In everyday writing the number is usually an Arabic numeral: 1月, 10月. The reading is the same either way.

April, July and September

The numbers 4, 7 and 9 each have two readings, and in normal counting the safer choices are よん, なな and きゅう. Month names go the other way. They're fixed words, and they use the other reading:

• 四月 is しがつ (shigatsu). よんがつ is wrong.
• 七月 is しちがつ (shichigatsu). You'll occasionally hear なながつ said on purpose, on the phone or in an announcement, because しちがつ is easy to mishear as いちがつ. Learn しちがつ as the standard.
• 九月 is くがつ (kugatsu), never きゅうがつ.

There's more on why those numbers have two readings in our post on Japanese numbers in kanji.

Days of the month

A date needs a day, and the first ten days don't follow the number plus にち pattern. They use native Japanese counting words that end in か. The 14th, 20th and 24th are irregular too.

Every other day is the regular number followed by にち: 十一日 is じゅういちにち, 十五日 is じゅうごにち, 三十一日 is さんじゅういちにち. The only thing to watch is that 7 and 9 are again しち and く here. The 17th is じゅうしちにち, the 19th is じゅうくにち, and the 27th and 29th follow suit.

Two pairs get confused constantly. よっか (the 4th) and ようか (the 8th) differ only by a short pause versus a long vowel. And 二日 (ふつか, the 2nd) and 二十日 (はつか, the 20th) sound alike when spoken quickly. When a date matters, such as a reservation, it's normal to confirm it by repeating it back.

The か words double as durations. 三日 (みっか) can mean the 3rd or three days, and 十日 (とおか) can mean the 10th or ten days. The exception is 一日: read ついたち it's the 1st of the month, and read いちにち it means one day.

Putting a date together

Japanese dates run from large to small: year, month, day. October 24, 2026 is written 2026年10月24日 and read にせんにじゅうろくねん じゅうがつ にじゅうよっか. A day of the week often follows in parentheses, as in 10月24日（土）. Our post on the days of the week covers those.

• 今日は何月何日ですか。 (きょうは なんがつ なんにち ですか, kyou wa nangatsu nannichi desu ka) What's the date today?
• 誕生日は四月二十日です。 (たんじょうびは しがつ はつか です, tanjoubi wa shigatsu hatsuka desu) My birthday is April 20th.
• 七月一日から休みです。 (しちがつ ついたち から やすみ です, shichigatsu tsuitachi kara yasumi desu) I'm off from July 1st.

Counting months with か月

三月 is March. Three months, as a length of time, is 三か月 (さんかげつ). The counter is か月, and two things change compared with the month names. 月 is read げつ instead of がつ, and 4, 7 and 9 go back to their everyday readings.

八か月 can also be read はっかげつ, and 十か月 has a more traditional reading, じっかげつ, that you'll hear from newsreaders. To ask how many months, say 何か月 (なんかげつ).

You'll see the counter spelled several ways: か月, ヶ月, ヵ月, カ月 and occasionally 箇月. They're all the same word. The small ヶ looks like a katakana ke but is read か. For six months, people often say 半年 (はんとし, half a year) instead of 六か月.

日本に三か月住んでいました。 (にほんに さんかげつ すんでいました, nihon ni sankagetsu sunde imashita) I lived in Japan for three months.

Counters are a big topic of their own. If か月 is your first one, our guide to Japanese counters goes through the rest.

This month, last month, next month

The words for months relative to now also use the げつ reading:

• 今月 (こんげつ, kongetsu): this month
• 来月 (らいげつ, raigetsu): next month
• 先月 (せんげつ, sengetsu): last month
• 再来月 (さらいげつ, saraigetsu): the month after next
• 毎月 (まいつき, maitsuki): every month. まいげつ is also used.

So 月 has three readings to keep apart. It's がつ in the name of a month, げつ in durations and in words like 来月 and 月曜日 (げつようび, Monday), and つき when it stands alone meaning "moon" or "month".

The traditional month names

Before Japan adopted the Western calendar in 1873, it used a calendar tied to the phases of the moon, and the months had poetic names as well as numbers. Nobody uses them to state a date now, but they haven't disappeared. They're printed on many calendars, they show up in poetry, seasonal greetings and the names of sake and sweets, and a few are used as personal names.

Treat the meanings as traditions rather than settled etymology. Several are disputed. 水無月 looks like "month without water", but the 無 is generally thought to be an old particle meaning "of", which fits the month when the rice fields are flooded. 文月 is also read ふづき.

The best-known story belongs to 神無月. In the tenth month of the old calendar, all the gods of Japan are said to leave their home shrines and gather at Izumo in Shimane Prefecture. Everywhere else it's the month without gods. In Izumo the same month is called 神在月 (かみありづき), the month when the gods are present.

The one you're most likely to hear is 師走. It's still an everyday word for December, especially for the rush at the end of the year, when even priests are supposed to be running around. 弥生 and 皐月 survive as the girls' names Yayoi and Satsuki. Because the old calendar ran several weeks behind the modern one, the seasonal meanings can feel slightly off: the old fifth month fell in the rainy season, which is why early-summer rain is 五月雨 (さみだれ).

Common questions