Is Zakat calculated on the amount available at the end of the Hawl (lunar year) (80,000 AED), or on the Nisab amount (51,000 AED), and can Zakat be paid in advance?

The zakat (definition) threshold for money in the form of banknotes or trade goods is estimated using silver, which is more cautious and beneficial for the poor. If the amount reaches eighty thousand Moroccan Dirhams and a full year has passed, zakat becomes obligatory because it has reached both the gold and silver thresholds. A quarter of one-tenth (2.5%) of it must be given. Even if the amount is less than the gold threshold, zakat must be paid as long as it has reached the silver threshold. It is permissible to pay zakat before the completion of the year, and the amount to be disbursed is based on its value at the time of disbursement. A quarter of one-tenth (2.5%) of the existing amount is given, as long as it meets the threshold.