Q: A person who has wealth equivalent to 200 dirhams should take out zakaat. How should a person work out the 200 dirhams into his currency? I live in South America and there is no one who can help me with this. Do I work it out from the Emirati Dirham?
A: The equivalent of 200 dirhams of silver is 612.36 grams of silver. Hence, work out the value of that amount of silver and that is the price of 200 dirhams. Presently it is R 4292.64 which is equal to approximately $405.14
And Allah Ta’ala (الله تعالى) knows best.
نصاب الذهب عشرون مثقالا والفضة مئتا درهم ، كل عشرة دراهم وزن سبعة مثاقيل … إلخ (شامي 2/295)
اوزانِِ شرعیّة ص62 (ادارة المعارف کراچی)