Allah(Swt) has generally stated in the Holy Quran that Zakat is obligatory on wealth. However, the amount of Zakat is not fixed at 2.5 percent for every single type of property. Instead, it changes depending on the kind of wealth a person owns.
For example, if someone owns a sheep farm and the number of sheep reaches a certain limit (called Nisab), Sheep must be given as Zakat in accordance with the prescribed calculation. If a person has one hundred, two hundred, or five hundred sheep, they must give exactly what Islamic law has decided. For instance, It is stated that a person owning between 40 and 120 goats must give one goat as Zakat. Based on this calculation, it would not amount to 2.5 percent. Similarly, for those who own cows or camels, the Zakat must be calculated using fixed rules, such as a set amount for every 40 to 50 cows.
During the time of the Companions (Sahaba) of the Prophet (peace be upon him), sheep, cows, and camels were the main forms of wealth. They fulfilled their Zakat directly from these animals. They gave sheep for sheep, cows for cows, and camels for camels, rather than working it out based on percentage. Therefore, these types of assets should not be included in the 2.5 percent calculation applicable to gold, silver, and cash. Instead, we must follow the specific rules given in Islam for each type of wealth, as this is our duty.
Just like livestock, Zakat (known as Ushr) is also compulsory for agricultural crops. The Zakat rate for things grown from the land—like dates, paddy, wheat, and rice—is not 2.5 percent. Instead, it has its own special rules: it is 10 percent for land watered naturally by rain, and 5 percent for land watered by artificial methods.
Apart from livestock and farming, there is also a special rule for hidden treasures. If someone finds a buried treasure, they must give 20 percent (one-fifth) of it as Zakat. Here too, the 2.5 percent rule does not apply. For example, if you find a treasure worth one hundred rupees, you must give twenty rupees as Zakat.
In this way, Islam provides clear and specific rules for certain types of wealth. For any other business goods or personal savings that do not fall under these categories, you must calculate their total value based on today’s money and pay Zakat at the rate of 2.5 percent.
We can see in detail later on the detailed laws as to what zakat is payable by what class of wealth. Here, however, we must know primarily that the amount of zakat varies according to the kinds of wealth.