What is the amount of zakat due on a monthly salary, bearing in mind that the salary is deposited into a bank account and it is not possible to determine the exact amount of money on which a whole year has passed (hawl)?

Whoever delays the Zakat beyond its due time must repent and pay the Zakat immediately. The time when the wealth reaches the nisab is calculated according to the Hijri date. The nisab is equivalent to 85 grams of gold or 595 grams of silver. Wealth is subject to Zakat after a full Hijri year has passed on it. It is permissible to combine the Zakat of all wealth in one year for ease. Wealth that was spent before the completion of the hawl (one year) is not subject to Zakat. One must review their accounts to determine the exact amount of Zakat due. If it is not possible to determine it precisely, then an estimation should be made to absolve oneself of responsibility.