What is the ruling for one who doubts whether zakat is due on money he possessed years ago, and he cannot recall if a hawl (lunar year) passed on it, or if he paid zakat on it, knowing that he experiences frequent doubt and obsessive thoughts? And what is the minimum amount for which zakat is likely to be due if the price of one gram of silver is less than a quarter of a Saudi riyal, according to those who calculate the nisab for money based on the nisab for silver?

The fundamental principle is the presumption of innocence from obligation. As long as the questioner doubts the obligation of Zakat on her wealth, the default is that it is not obligatory. The nisab (minimum threshold) for Zakat on silver is 595 grams. If the wealth reaches this amount and a full year has passed over it, then Zakat becomes obligatory on it, which is a quarter of a tenth (2.5%). The nisab is calculated by the lower value of the two currencies, and it is advised to avoid obsessive doubting (waswasah).