Estimate zakāt on gold using the rules in the Zakat Jurisprudence of Individuals
document: nisāb is 85 g of pure gold; the rate is
2.5% (one quarter of one tenth, i.e. divide the zakatable value by
40). A full lunar year (~354 days) must pass while you
hold the wealth at or above nisāb.
Calculator
Weight per karat (grams, optional rows — at least one)