Nisab is measured either 1) separately (for gold, silver, cash, stocks, and other exchangeable monetary instruments, and trade goods), by measuring the nisab separately for each zakatable category; or 2) if individual measures fall below the nisab amount, it is obligatory to combine individual measures from each category (of gold, silver, and so on) to determine the total amount of zakatable property; livestock is always measured separately.
Zakat is only obligatory on property possessed at both ends of the lunar year; therefore if during the year the value of the property exceeds the nisab and subsequently, more property which is held for less than one year, is added to the original amount, zakat is paid on the new amount (i.e. zakat is paid on the original property held for one year plus new property held for less than one year).
