なくてもいい
Don't have to
Structure
Explanation
なくてもいい functions as the negative counterpart to てもいい, expressing that there is no obligation to do something. It often conveys a polite nuance, similar to saying 'you don't need to do (A)' in English.
なくてもいい is formed by attaching もいい to the te-form of a negated verb, which ends in なくて.
- その映画はあまり面白くないから、見なくてもいいですよ。That movie isn't very interesting, so you don't have to watch it.
- そのお皿は洗わなくてもいい。It's fine if you don't wash those dishes.
For a more informal feel, the particle も can be left out, resulting in なくていい. This doesn't alter the core meaning but creates a more relaxed and friendly tone, suitable for use with people you are close to.
- 全部食べなくていいよ。You don't have to eat it all.
Examples
時間があるなら、急がなくてもいいです。
If there is time, you don't have to rush.
宿題は、手伝わなくてもいいですか。
Is it alright if I don't help with the homework?
大丈夫だから、そんなに心配しなくてもいいですよ。
It's going to be alright, so you don't have to worry so much.
もし嫌いなら、食べなくてもいい。
If you don't like it, you don't have to eat it.
明日でも大丈夫だから、今すぐ返さなくてもいい。
Tomorrow is fine, so you don't have to return it right now.
傘は持って行かなくてもいい？
Is it okay if I don't bring an umbrella?
先生が、今日の授業料は払わなくてもいいと言っていたよ。
The teacher said that it's alright if we don't pay for today's class.
食洗機があるから、お皿は洗わなくてもいいだろう。
Since we have a dishwasher, we probably don't have to wash the dishes.
そのレストランはいつも空いているので、予約をしなくてもいい。
That restaurant is always empty, so you don't have to make a reservation.
コンビニで何かを買えば、夕食は作らなくてもいい。
If I buy something at the convenience store, then I don't have to make dinner.
全部読まなくてもいいよ。大事なところだけを読めば十分だ。
You don't have to read the whole thing. It is enough if you just read the important parts.
もう遅いよ。まだ寝なくてもいいの？
It's already late. Is it really okay for you not to go to sleep yet?