Praise be to Allaah.
It was narrated that the Messenger of Allaah (peace and blessings of Allaah be upon him) enjoined zakaat al-fitr upon the Muslims at a rate of one saa’ of dates or one saa’ of barley, and he commanded that it should be given before the people went out to pray – i.e., the Eid prayers. In al-Saheehayn it is narrated that Abu Sa’eed al-Khudri (may Allaah be pleased with him) said: “At the time of the Messenger of Allaah (peace and blessings of Allaah be upon him) we used to give it at a rate of one saa’ of food, or one saa’ of dates, or one saa’ of barley, or one saa’ of cheese, or one saa’ of raisins…” A number of scholars interpreted the word ta’aam (food) in this hadeeth as referring to wheat, and others explained it as referring to the staple food of the local people, no matter what it is, whether it is wheat, corn or something else. This is the correct view, because the zakaah is a kind of help given by the rich to the poor, and the Muslim should not offer help with anything other than the staple food of his country. What must be given is a saa’ of all kinds of food, which is four times the amount scooped up with two hands, which is approximately three kilograms. If the Muslim gives a saa’ of rice or some other staple food of his country, that is fine.

It first becomes due on the night of the twenty-eighth of Ramadaan, because the companions of the Prophet (peace and blessings of Allaah be upon him) used to give it one or two days before Eid, and the month lasts twenty-nine or thirty days.
The latest it may be given is at the Eid prayer, but it is not permissible to delay it until after the prayer, because of the report narrated by Ibn ‘Abbaas (may Allaah be pleased with him), that the Prophet (peace and blessings of Allaah be upon him) said: “Whoever gives it before the prayer, it is accepted zakaah, and whoever gives it after the prayer, it is a kind of charity.” (Narrated by Abu Dawood).

It is not permissible to pay the value in money, according to the majority of scholars, and the evidence for this view is more sound. Rather it should be given in the form of food, as was done by the Prophet (peace and blessings of Allaah be upon him), his companions (may Allaah be pleased with them) and the majority of the ummah. We ask Allaah to help us and all the Muslims to understand His religion and adhere steadfastly to it. May Allaah bless our Prophet Muhammad and his family and companions.

Deen4me:
Volume not weight please

1 kg of rice will not be the same as 1 kg of beans, dates, millet, etc

Kindly correct and use volume