1. At the time of sunset on Eid ul fitr night (i.e. the night preceding Eid day), whoever is adult and sane and is neither unconscious, nor poor, nor the slave of another, he should give, on his own behalf as well as on behalf of all those who are his dependents, about three kilos per head of wheat or barley or dates or raisins or rice or millet etc.
It is also sufficient if he pays the price of one of these items in cash. As per obligatory precaution, he should not give from that food which is not staple in his place, even if it be wheat, barley, dates or raisins.
2. If a person is not in a position to meet his own expenses, as well as those of his family, for a period of one year, and has no job or work from which he can have income to cover his and his family expenses for one year, then he is a poor person, and it is not obligatory on him to pay Zakat of fitrah.
3. One should pay Fitrah on behalf of all those persons who are treated as his dependents at his house on the nightfall of Eid ul fitr, whether they be young or old, Muslims or non-Muslims; irrespective of whether or not it is obligatory on him to maintain them, and whether they are in his own town or in some other town.
4. If a person appoints his dependent who is in another town, to pay his own fitrah from his property, and is satisfied that he will pay the fitrah, it will not be necessary for the person to pay that dependent's fitrah.
5. It is obligatory to pay the fitrah of a guest who arrives at his house before sunset on Eid ul fitr night, and becomes his temporary dependent .
6. The fitrah of a guest who arrives at his house on the night of Eid ul fitr after sunset, and becomes his temporary dependent, is also, as per obligatory precaution, wajib upon the host. If a guest arrives on Eid ul fitr night, for iftar, his Fitrah is not wajib on host, because he is not dependent on host.
7. If a child becomes baligh, or an insane person becomes sane, or a poor person becomes self sufficient during sunset, and satisfies the conditions, fitrah becoming obligatory on him, he should give fitrah.
8. If it is not obligatory on a person to pay fitrah at the time of sunset on the night of Eid ul fitr, but necessary conditions making fitrah obligatory on him develop before Zuhr on Eid day, the obligatory precaution is that he should pay fitrah.
9. If a non-Muslim becomes a Muslim after the sunset on the night of Eid ul fitr, it is not obligatory on him to pay fitrah. But if a Muslim who was not a Shi'ah becomes a Shi'ah after sighting the moon, he should pay fitrah.
10. It is Mustahab that a person who affords only one sa'a (about 3 kilos) of wheat etc. should also pay fitrah. And if he has family members and wishes to pay their fitrah as well, he can give that one sa'a to one of his family members with the intention of fitrah and that member can give it to another family member, and so on, till the turn of the last person comes; and it is better that the last person gives what he receives to a person who is not one of them. And if one of them is a minor or insane, his guardian can take fitrah on his behalf.
11. If one's child is born after the sunset on the night of Eid ul fitr, it is not obligatory to give its fitrah.
12. If one who was dependent of a person, and becomes dependent of another before sunset, fitrah is obligatory on the other person whose dependent one has become. For example, if one's daughter goes to her husband's house before sunset, her husband should pay her fitrah.
13. If the fitrah of a person is obligatory on another person, it is not obligatory on him to give his fitrah himself.
14. If it is obligatory on a person to pay the fitrah of another person, but he does not pay it, its payment will be, as an obligatory precaution, obligatory on the latter. So, if all the conditions mentioned in rule 1 are fulfilled, he must pay his own fitrah.
15. If it is obligatory on a person to pay the fitrah of another person, his obligation will not end if the latter himself pays his own fitrah.
16. A person, who is not a Sayyid, cannot give fitra to a Sayyid, and if the Sayyid is his dependent, he cannot give his fitra to another Sayyid either.
17. The fitrah of a child who sucks the milk of its mother or a nurse, is payable by one who bears the expenses of the mother or the nurse. But, if the mother or the nurse is maintained by the property of the child itself, payment of fitrah for the child is not obligatory on any one.
18. Even if a person maintains the members of his family by haraam means, he should pay their fitrah out of halal property.
19. If a person employs someone like a carpenter, or a servant, and agrees to maintain him fully, he should pay his fitrah as well. But if he agrees that he would pay him for his labour, it is not obligatory on him to pay his fitrah.
20. If a person dies before sunset on the night of Eid ul fitr, it is not wajib to pay his fitrah or that of his family, from his estate. But if he dies after sunset, it is commonly held that fitrah will be obligatory, but it is not devoid of Ishkal. However, it is better to act on precaution, and pay his fitrah as well as that of his family.
These laws are according to Aayatullah Sistani's Fataawa.