YOU SAID:

I have to go to school next tuesday

INTO JAPANESE

私は次火曜日に学校に行かなければなりません

BACK INTO ENGLISH

I do not have to go to school next Tuesday

INTO JAPANESE

私は次火曜日に学校に行く必要はありません

BACK INTO ENGLISH

I do not need to go to school next Tuesday

INTO JAPANESE

私は次火曜日学校に行く必要はありません

BACK INTO ENGLISH

I do not need to go to school next Tuesday