Here is a table that displays each wealth type, it’s prophetically delimited niṣâb in value equivalence, and that wealth stream’s Zakat rate (also specified by the Prophet, on him be peace).
The niṣâb value for personal, business, and discovered wealth is the current worth of 85 grams of pure gold (approx. 3 U.S. ounces). 1
The niṣâb of agricultural produce is 1,439 lb. (653 kg).
The niṣâb for ovine (sheep and goats) is 40 head.
The niṣâb for bovine (cattle, buffalo, bison, antelope, yaks, etc.) is 30. 2
He set it for camels at 5.
For a comprehensive explanation about how we know our measures of niṣâb for wealth today are the same as what the Prophet, on him be peace, established see How Is Zakat Calculated on Wealth?
How long after wealth reaches its niṣâb does it come due?
Zakat on most Zakatable wealth comes due when it reaches niṣâb after the passage of an Islamic lunar year. The Islamic year is called the Hijri year, and its period for the purposes of determining Zakat payment is called a ḥawl.
One calculates a hawl (Zakat year) from whatever date one’s Zakatable wealth reaches the “minimum threshold” of niṣâb for that type of wealth until an entire 12 hijri months pass. That final day becomes a payer’s Zakat Due Date (ZDD) (see When Is Zakat Due?)
Do changes in niṣâb change when Zakat comes due?