なくちゃ・なきゃ

Casual contractions of なくてはいけない, used to express strong obligation or necessity in everyday speech. なくちゃ is slightly more formal than なきゃ, but both are very common in spoken Japanese. They typically attach to the negative form of a verb (Vない) to mean “have to do X” or “must do X.” They convey immediacy or personal obligation rather than neutral necessity. 2 common patterns: なくちゃ (strictly spoken) and なきゃ (more casual). Note that with い-adjectives or other word classes, the construction is primarily used with verbs; for adjectives and nouns, listeners often use similar forms with 〜なくちゃいけない or 〜じゃないといけない in more formal contexts. Examples show everyday urgency, plans, or reminders.