How to Pay Zakah from a Monthly Salary

Q: I am a Muslim who works in the government sector, and I receive a monthly income like any other government employee. At many times, I save an unspecified amount of money from the monthly salary depending on circumstances. For example, in one month I might be able to save 2,000 riyals, in another month 4,000 riyals, and in another month I might not be able to save anything. As days and months pass, I end up with a considerable amount of money.
So, is zakah obligatory on it? And how can I determine this? Is it by the passage of a full lunar year on each amount of money, since I do not follow a specific system for saving, which makes determining the lunar year difficult? I am afraid that I may have disobeyed Allah’s command regarding zakah without knowledge or understanding. Therefore, I ask your eminence to clarify this. May Allah reward you with good.

A: It is obligatory for you to pay the zakah of each amount when its lunar year has passed, and you should record this in writing so that you are on clear knowledge. If you pay the zakah of the entire amount when the lunar year has passed on the first saving, that is sufficient and your liability is cleared, because paying zakah before the completion of its lunar year is permissible. And success is from Allah.