do not have to

The negative te-form plus もいい grants exemption: it is fine even if you do not do it. It is the opposite of なければならない. In casual speech the も is often dropped: 行かなくていい.

Examples

• 明日あしたは来こなくてもいいです。

  Ashita wa konakute mo ii desu.

  You do not have to come tomorrow.

• 靴くつを脱ぬがなくてもいいですか。

  Kutsu o nuganakute mo ii desu ka.

  Is it okay if I do not take off my shoes?

Vocabulary in these examples

• 明日 tomorrow
• 来る to come
• いい good; fine (also: no thank you)
• 靴 shoes
• 脱ぐ to take off (clothes)

Related patterns · Obligation and advice

• 〜なければならない must, have to
• 〜たほうがいい had better do, should do (advice)
• 〜たらどうですか how about doing, why not do