Is zakat obligatory annually on the fluctuating balance in a current account?

The easiest method for calculating zakat on money is to count one lunar year (Hawl) from the day the money reaches the Nisab (the equivalent of 85 grams of gold). Zakat is then paid on the amount of money present at the completion of the year, regardless of whether it increased or decreased during the year, as long as it did not fall below the Nisab. If it fell below the Nisab, the year count is interrupted, and a new year count begins. If the bank is usurious (Riba-based), you are required to withdraw your money from it and deposit it in an Islamic bank.