noun
how many months
Used to ask about a duration or number of months. Often followed by particles like も or か.
日本に来て何ヶ月になりますか。
How many months have you been in Japan?
このプロジェクトは何ヶ月かかりますか。
How many months will this project take?
Compound of 何 (nan, 'what') + ヶ (ka, counter for months) + 月 (getsu, 'month'). The ヶ is a simplified form of the kanji 箇.