How much is the zakat on saved money?

Zakat is obligatory on saved money if it reaches the nisab (minimum threshold) and a full hawl (lunar year) has passed on it. Its amount is a quarter of a tenth (2.5%), meaning twenty-five out of the mentioned amount. If the money is saved with usurious interest, Zakat is obligatory only on its principal, and the interest must be disposed of by spending it on charitable causes, while withdrawing the money unless there is a necessity for its presence, such as fear of its loss and the absence of an Islamic bank.