ALLAAHu ladhi la ilaha illa huwa
( ALLAAH whom there is no God expect He)
Nisaab ul-Zakat for naqd (gold and silver) is defined as the minimum amount of naqd specified by shari’a below which one is not required to pay zakat, whereas if one’s wealth exceeds it then zakat becomes incumbent.
And it is known that zakat ul-maal (wealth) in shari’a is required for the two types of naqd—gold and silver—and what serves their function in modern times (commonly referred to as cash), whether it is dollars or riyals or pounds or otherwise.
Nisaab for gold as our Prophet (peace be upon him) has informed us (and for currencies made from gold) is 20 mithqaalan, a measure which is equivalent to 85 grams of pure gold (1 mithqaal = 4.25 grams). It becomes incumbent upon anyone who owns such an amount in any form to pay zakat on it in the amount of 2.5%.
Nisaab for silver and currencies made from silver is 200 dirhams, which is equivalent to 595 grams of pure silver (1 dirham = 2.975 grams). Likewise, it becomes incumbent upon anyone who owns such an amount in any form to pay zakat on it in the amount of 2.5%.
(sheik saalih Muhammad Al-Munajjid)
ALLAAH knows best