Every Muslim, male or female, who, at the end of the year, is in possession of the nisab (minimum Zakah - able wealth) approximately the value of 85 grams of gold or more, in cash or articles of trade, must give Zakah at the minimum rate of two and one-half percent. In the case of having the amount in cash the matter is easy. But when a person has wealth in business stocks or trade articles, he must evaluate his wealth at the end of every year according to the current value and give Zakah at the same rate of two and one-half percent of the total value of the wealth. If his investment is in immovable property like revenue buildings and industries, the rate of Zakah should go by the total net of the income, and not of the total value of the whole property. But if he puts up buildings and houses for trade or selling, Zakah rate should go by the total value of the entire property. Also if someone is a creditor and the indebted person is reliable, one should pay Zakah for the amount he has lent because it is still a portion of his guaranteed wealth.
In all cases it should remembered that one pays only for his net balance. His personal expenses, his family allowances, his necessary expenditures, his due credits – all are paid first, and Zakah is for the net balance.
It should also be remembered that the rate of 2.5% is only a minimum. In times of emergency or arising needs there is no rate limit; the more one gives, the better it is for all concerned, the distribution of Zakah serves all purposes for which numerous fund-raising campaigns are launched. The Zakah fund substitutes for all the other funds. It is authentically reported that there were times in the history of the Islamic administration when there was no person eligible to receive Zakah; every subject – Muslim, Christian, and Jew - of the vast Islamic empire had enough to satisfy his needs, and the rulers had to deposit the Zakah collections in the Public Treasury. This shows that when the Zakah law is enacted properly it minimizes the needs of the citizens and enriches the Public Treasury to such an extent that there may be no needy or poor, and that enormous amounts of surplus are available.
The unfailing power of this effective measure of public interest stems from the fact that it is a Divine injunction, an ordinance from God Himself. It is not a personal matter or a voluntary contribution; rather, it is an obligation for the fulfillment of which one will be responsible to God directly. Because Zakah is the legislation of God Himself to be enforced in the common interest, no Muslim is allowed to neglect it. When it is not observed properly, the rightful authorities of the State must interfere on behalf of the public to establish the institution and see to it that it is enforced.