Months in Japanese is a little confusing. There are three ways to say month which are がつ Gatsu, つき Tsuki, and かげつ Kagetsu. The difference is as follows.
- がつ (月 in Kanji) Gatsu … for the name of each month (January, February, etc.)
- つき (月 in Kanji) Tsuki … for counting months with traditional Japanese numbers
- かげつ (か月 or ヶ月 using Kanji) Kagetsu … for counting months with Chinese numbers
Name of Months in Japanese
Unlike English where each month has a specific name assigned, we use numbers いち (ichi) に (ni) さん (san) し (shi) to name months in Japanese.
- January １月 – いちがつ Ichi gatsu
- February ２月 – にがつ Ni gatsu
- March ３月 – さんがつ San gatsu
- April ４月 – しがつ Shi gatsu (Not Yon gatsu)
- May ５月 – ごがつ Go gatsu
- June ６月 – ろくがつ Roku gatsu
- July ７月 – しちがつ Shichi gatsu (Not Nana gatsu)
- August ８月 – はちがつ Hachi gatsu
- September ９月 – くがつ Ku gatsu (Not Kyuu gatsu)
- October １０月 – じゅうがつ Juu gatsu
- November １１月 – じゅういちがつ Juuichi gatsu
- December １２月 – じゅうにがつ Juuni gatsu
Just be careful with April, July, and September since we have two ways to say four, seven and nine in Japanese.
Counting Months in Japanese
When you simply count months as in one month, two months, or three months, you can either use つき (Tsuki) or かげつ (Kagetsu).
The literal meaning of つき (Tsuki) is “moon.” It takes traditional Japanese numbers, and we count up to three months with つき (Tsuki) in modern Japanese.
- One month ひと月（ひとつき Hito
- Two months ふた月（ふたつき Futa
- Three months み月（みつき Mi
かげつ (Kagetsu) takes Chinese numbers, and you can count as many months as you want with this one.
- One month １か月（いっかげつ Ikkagetsu)
- Two months ２か月（にかげつ Ni kagetsu)
- Three months ３か月（さんかげつ San kagetsu)
- Seventeen months １７か月（じゅうななかげつ Juunana kagetsu)
How are they different? つき vs. かげつ
You can use either one when you want to mention the duration of time as in “for one month” in your sentence. It is your personal preference.
Example: I stayed in Japan for one month.
日本にひと月いました。Nihon ni hito
日本に１か月いました。 Nihon ni
Please note that you don’t mark the duration of time with the Time Marker に NI, which is used to mark a point of time such as “AT 5:00” or “ON Sunday.”
So this is wrong.
日本にひと月にいました。Nihon ni hito tsuki NI imashita.
When you use months to indicate the age of a baby, you use かげつ (Kagetsu).
Example: My son is now five months old.
むすこは今、５か月です。Musuko wa ima gokagetsu desu.
Download the Chart – Japanese Months
I have the chart for Japanese months (PDF) that I created in Romaji, Hiragana, and Kanji. Provide your name and email address below. I will send it to you right away.