一いっヶか月げつ

い

っ

か

げ

つ

Common word

Meanings

1

noun

one month

Standard counter for a duration of one month. Used with 間 (かん) to emphasize duration, e.g., 一ヶ月間.

一いっヶか月げつに一いち度ど、病びょう院いんに行いきます。
I go to the hospital once a month.
このプロジェクトは一いっヶか月げつで終おわらせます。
I will finish this project in one month.

Written forms

一いっヶか月げつ
Most common kanji spelling; the small ヶ is a counter marker.
一ヵ月いっかげつ
Variant with small ヵ; less common but still seen.
一いっカか月げつ
Variant with full-size カ; often used in vertical writing or older texts.
一いっか月げつ
Hiragana か variant; common in informal writing.
一いっ箇か月げつ
Formal or legal spelling using 箇; rarely used in everyday writing.
一いっケか月げつ
Variant with large ケ; mostly seen in older documents.
１いっヶか月げつ
Arabic numeral variant; common in digital text and casual writing.
１ヵ月いっかげつ
Arabic numeral with small ヵ.
１いっカか月げつ
Arabic numeral with full-size カ.
１いっか月げつ
Arabic numeral with hiragana か.
１いっ箇か月げつ
Arabic numeral with formal 箇.
１いっケか月げつ
Arabic numeral with large ケ.

Kanji

一one, one radical (no.1)
月month, moon
箇counter for articles

Similar words

一いっか月げつ間かん
Explicitly marks the duration of one month; 一ヶ月 can also be used with 間, but 一か月間 is more precise for emphasizing the period.
一ひと月つき
Also means 'one month', but 一月 (ひとつき) is more colloquial and often used in spoken Japanese, while 一ヶ月 is slightly more formal and common in writing.

Etymology

Compound of 一 (いち, 'one') + ヶ (a counter marker derived from 箇) + 月 (げつ, 'month'). The reading いっかげつ results from a sound change where いち + か becomes いっか.