What is the method for paying Zakat on a variable monthly salary, taking into account the fluctuating Nisab value from time to time, and how is the Nisab calculated for savings accumulated over the years? Is it permissible to delay paying Zakat beyond its due time, and is it possible to pay 2.5% of the salary monthly as Zakat in advance? What is the meaning of Sheikh Ibn Uthaymeen's statement: "And the Zakat will be due at its proper time upon the completion of the Hawl (lunar year), and for what comes after it, it will be paid in advance, and advancing payment is permissible"?

The calculation of the [hawl] (lunar year) begins on the day one possesses the [nisab] (minimum taxable amount), and zakat is paid at its end. If the [hawl] concludes before Eid al-Fitr, it is not permissible to delay the zakat. The nisab for banknotes is the lower of the two nisabs, gold or silver. If the money falls below the nisab during the [hawl], the zakat is waived. If one acquires a nisab again, a new [hawl] is calculated. If one benefits from new money of the same type as money already possessed, it is added to the initial money for the nisab, but not for the [hawl]. It is not permissible to delay zakat unless its rightful recipient is not found, and the presence of just one of the eight categories of recipients is sufficient. It is not obligatory to pay zakat on salary except for what exceeds one's needs and reaches the nisab.