Is Zakat obligatory on money saved in the bank for marriage, and what is the method of paying its Zakat, and does distributing the interest from this money to the poor suffice for its Zakat?

It is forbidden to deposit money in an interest-based (usurious) bank. It is obligatory to withdraw it and deposit it in an Islamic bank if available, or to keep it in any other place. If you are compelled to place it in an interest-based bank, then put it in a current account to avoid interest. If you receive usurious interest, it is not permissible to benefit from it. It must be spent on charitable causes, such as helping the poor or for the benefit of Muslims. Distributing this interest does not exempt one from paying the obligatory Zakat on this saved money if it reaches the nisab (minimum threshold) and a hawl (one lunar year) has passed on it. Its amount is one-quarter of one-tenth (2.5%).