The Japanese grammatical expression なくてもいい is used to express that something is not necessary or not required. It can be translated as it's okay not to or don't have to in English. This expression is formed by combining the negative て-form of a verb (ない-form changed to なくて) with も いい, which means it's okay or it's fine.
|It's okay not to eat.
|食べなくて も いい。tabenakute mo ii.
|You don't have to go.
|行かなくて も いい。ikanakute mo ii.
|You don't need to bring anything.
|何も 持って 来なくて も いい。nanimo motte konakute mo ii.
|Since it's raining, I don't have to go out.
|雨 だ から、 出かけなくて も いい。ame da kara, dekakenakute mo ii.