How is Zakat calculated on a sum of money that has reached the Nisab, but on which Zakat has not been paid previously, given that it has been owned for three years or more? Is it permissible to pay Zakat for only one year? Does the calculation of the hawl (one lunar year) begin from the date of the intention to pay Zakat, or from the date of possessing the money? And can a specific amount for Zakat be fixed for business money that fluctuates (increases and decreases)?

It is obligatory to pay zakat (definition) on the accumulated sum immediately upon the completion of its

Hijri year, provided it reaches the nisab (definition). You must seek forgiveness for what has passed

and pay zakat for the previous years by estimating the amount present in each year. It is

not permissible to designate a specific amount for zakat that is less than what you

possess; rather, it is obligatory to pay zakat on all the cash and trade goods you own

upon the completion of the year.