Ruling 1783 — The One-Fifth Tax (Khums)

During the year, a person can pay khums on his profit whenever he acquires it, and it is also permitted (jāʾiz) for him to delay paying khums until the end of the year. However, if he knows that he will not need it until the end of the year, then based on obligatory precaution, he must pay khums on it immediately. Furthermore, there is no problem if one adopts the solar year for the payment of khums.