GRAMMAR DETAIL
なくてもいい
Follows the negative connective form of a verb to show that not performing an action is permitted or causes no problem.
Examples
明日は休みだから、早く起きなくてもいい。
Tomorrow is a day off, so I do not have to get up early.
Words used
急ぎでなければ、今日中に返さなくてもよい。
If it is not urgent, you do not have to return it today.
この書類には住所を書かなくてもいいです。
You do not have to write your address on this form.
Words used
Study notes
1. Origins, structure, and basic meaning
- Structure: Change the verb's negative ending
ないtoなくて, then addもいい. - Basic usage:
この書類には住所を書かなくてもいいです。means that writing an address is not required.
2. Common pitfalls and similar expressions
- Lack of necessity and prohibition
書かなくてもいいpermits not writing, while書いてはいけないprohibits writing. Distinguish leaving a choice open from forbidding an action.
- Which action is permitted
起きなくてもいいpermits not getting up, while起きてもいいpermits getting up. Check whether the action precedingいいis affirmative or negative.