The nisab is the minimum amount of wealth that a Muslim must own for Zakat to become obligatory. This threshold was established by the Prophet Muhammad (peace and blessings be upon him) and varies depending on the type of asset.

For wealth in the form of gold, the nisab is 20 dinars, which is equivalent to 85 grams of pure gold. For silver, the nisab is 200 dirhams, which is equivalent to 595 grams of pure silver. For modern currency, trade goods, and other monetary assets, the nisab is calculated based on the current market value of either gold or silver. Many scholars, including Shaykh Ibn 'Uthaymeen, suggest using the standard that is more beneficial to the poor. As the value of the silver nisab is currently much lower than the gold nisab, using it means that more people will pay Zakat, thus increasing the amount available for the needy.

Once a person's Zakatable wealth reaches the nisab, another condition must be met before Zakat is due: the passing of one full lunar year (known as the hawl) while the wealth remains at or above the nisab. If the wealth drops below the nisab during the year, the counting of the hawl resets. This condition applies to money, gold, silver, and trade goods.

Other categories of wealth have their own specific nisabs. For example, the nisab for sheep and goats is 40 animals, for cattle it is 30, and for camels it is 5. For agricultural produce, the nisab is five wasq (approximately 653 kilograms), and Zakat is due upon it at the time of harvest, not after a year.