On this issue, Dr. Monzer Kahf, a prominent economist and counselor stated that the amount of Zakatul Fitr is determined in the Hadith. It is one Sa’ of any of the main six food items that were common at the time of the Prophet (peace and blessings be upon him) and their similar items such as rice. The principle is to make the distribution in kind unless otherwise is more convenient and favorable to the poor. So, a Muslim should take the average kind (quality) of food item that is consumed by the Muslims of his area. No scientific survey is required in the payment of Zakah, instead, it is always by approximation and understanding.
Regarding its distribution, the priority us that it is given to the people of the community in which a person lives.
Concerning the amount of Kaffarah, it is the food of sixty poor normally two meals a day. It was approximated by the Prophet (peace and blessings be upon him) as 15 Sa’ (the Sa’ is approximately 2.55 kilograms). The principle remains food of two meals. The Fidiah is one day food.
Regarding zakah on income, it cannot be taken by analogy to agriculture for one who receives his salary in money, and the multiplicity of production in agriculture (one grain gives 700) does not exist in salaries. It is the closest to trade because in trade the trader spends his time to buy and sell and then Zakah is calculated at the end of the year on what is left, never on the gross amount of merchandise he bought and sold. What is left means after spending all personal and family expenses, including payment for the residence whether it is installments or rents. The Zakah here is on the savings if they reach Nisab over the period of a lunar year, the Nisab is approximately Euro 1000.
On the Interest earned from banks, it may be spent on the poor and needy and sick persons and those who became poor because of calamities etc.