How to Say "Three Months" in Japanese

3ヶ月

sankagetsu

The English phrase "three months" is translated into Japanese as 3ヶ月 (sankagetsu).

The phrase refers to a period of time lasting three months.

Which one should you use?

You may see the phrase written as 三ヶ月, which uses the Kanji for the number three (三) instead of the Arabic numeral 3.

sankagetsu

The small ヶ in 3ヶ月 is not a phonetic character from the katakana alphabet, but a stylistic shorthand for the kanji 箇.
In Japanese, using 3ヶ月 to mean 'three months' avoids a critical mistake, as saying 三月 (sangatsu) refers exclusively to the month of 'March'.
In high-level legal or traditional documents, the phrase is written as 三箇月, utilizing the full-sized kanji instead of the shorthand symbol.

3ヶ月前に自殺しました。
He killed himself three months ago.
This sentence is useful for seeing how to use 3ヶ月 when referring to a point in time in the past.
Tatoeba #12137323 by small_snow, translation #7383090 by CH
トムは3ヶ月も入院してたんだ。
Tom was in the hospital for a whole three months.
This sentence is useful for using 3ヶ月 to describe how long someone was in the hospital.
Tatoeba #12995349 by small_snow, translation #13023120 by end
このプロジェクトは3ヶ月かかります。
Kono purojekuto wa sankagetsu kakarimasu.
This project will take three months.
6 more sentences on Tatoeba

Misaki and Yota are talking about a seasonal training program.

陽太 Yota

そのトレーニングはどのくらい続くの？
Sono toreeningu wa dono kurai tsuzuku no?
How long does that training last?
美咲 Misaki

だいたい3ヶ月くらいだよ。
Daitai sankagetsu kurai da yo.
It's about three months.
陽太 Yota

3ヶ月も頑張らないと大変だね。
Sankagetsu mo ganbaranaito taihen da ne.
It will be tough to work hard for three months.
美咲 Misaki

うん、頑張るつもりだよ！
Un, ganbaru tsumori da yo!
Yeah, I intend to do my best!

Sources

⭐Share⭐ to appreciate human effort 🙏