Is zakat obligatory on the deferred dowry that is owed by the husband, whether the husband is able to pay it immediately or not, and what is the ruling on paying it if the custom is that the wife does not receive it except from her husband's estate?

The deferred dower (mahr) is like other debts; zakat is obligatory on it if it is due and the husband is capable of paying it. It is subject to zakat every time a year passes over it and it reaches the

nisab (minimum threshold). However, if the husband is insolvent or procrastinates in payment, then no zakat is due on it until it is received. When received, zakat is paid for one year only. If it is only due upon death or divorce, then no zakat is due on it until it is received, due to the absence of full ownership.