How is Zakat calculated on joint spousal wealth that exceeds the Nisab and fluctuates while remaining above the Nisab? Is it permissible to pay Zakat on the lowest amount available in the account throughout the year?

First: Zakat is not obligatory on money until it reaches the nisab (minimum threshold) and a hawl (full lunar year) passes over it. If it falls below the nisab during the hawl, the hawl is interrupted, and a new hawl begins when the nisab is reached again.

Second: For salaries and recurring income, a single hawl can be designated for the zakat of all accumulated money. What has not yet completed its hawl can be paid in advance if there is a need.

Third: If the balance is low in the last month and zakat is paid based on the actual balance, nothing more is required; because this balance is what has completed its hawl.

Fourth: Zakat can be calculated based on the annual average balance or its minimum once a year, ensuring that any surplus amount exceeding the minimum is paid zakat on when its hawl is due. The easiest and most prudent approach is to calculate zakat based on the balance of the last month of the year.