How is the nisab for zakat on money calculated, given the fluctuation in gold prices throughout the year? Is it by considering the highest prevailing price for most of the year, or by the price at the end of the year when the hawl is due?

A Muslim pays 2.5% of his zakatable assets if they reach the nisab. This amount does not change with the fluctuation in the value of gold, unless the zakat payer wishes to give gold itself as zakat. However, if the assets do not reach the nisab except through certain valuations, then the considered value is the value of gold at the time of paying zakat. The criterion for reaching the nisab is based on the value of gold or silver, whichever makes the wealth reach the nisab.