Zakah al-Fitr is often referred to as Sadaqah al-Fitr. The word Fitr means the same as Iftar, breaking a fast and it comes from the same root word as Futur which means breakfast. Thus, Islamically, Zakah al-Fitr is the name given to charity which is distributed at the end of the fast of Ramadan.
Sadaqah al-Fitr is a duty which is Wajib on every Muslim, whether male or female, minor or adult as long as he/she has the means to do so. The proof that this form of charity is compulsory can be found in the Sunnah whereby Ibn Umar reported that the Prophet (peace be upon him) made Zakah al-Fitr compulsory on every slave, freeman, male, female, young and old among the Muslims; one Sa of dried dates or one Sa of barely. [Reported by Al-Bukhari]
The head of the household may pay the required amount for the other members. Abu Sa'id al-Khudri said, "On behalf of our young and old, free men and slaves, we used to take out during Allah's Messenger's (peace be upon him) lifetime one Sa of food, cheese, grain, dates or raisins". [Reported by Muslim]
The significant role played by Zakah in the circulation of wealth within the Islamic society is also played by the Sadaqah al-Fitr. However, in the case of Sadaqah al-Fitr, each individual is required to calculate how much charity is due from himself and his dependents and go into the community in order to find those who deserve such charity. Thus, Sadaqah al-Fitr plays a very important role in the development of the bonds of community. The rich are obliged to come in direct contact with the poor, and the poor are put in contact with the extremely poor. This contact between the various levels of society helps to build real bonds of brotherhood and love within the Islamic community and trains those who have, to be generous to those who do not have.
The main purpose of Zakah al-Fitr is to provide those who fasted with the means of making up for their errors during the month of fasting. Zakah al-Fitr also provides the poor with a mean with which they can celebrate the festival of breaking the fast (Eid al-Fitr) along with the rest of the Muslims. Ibn Abbas reported, "The Prophet (peace be upon him) made Zakah al-Fitr compulsory so that those who fasted may be purified of their idle deeds and shameful talk (committed during Ramadan) and so that the poor may be fed. Whoever gives it before Salah will have it accepted as Zakah, while he who gives it after the Salah has given Sadaqah." [Reported by Abu Dawud and Shaikh Naser Al-Albani said it is Hasan (good)]
Hence, the goal of Sadaqah al-Fitr is the spiritual development of the Believers. By making them give up some of their wealth, the believers are taught the higher moral characteristics of generosity, compassion (sympathy for the unfortunate), gratitude to God and the righteousness. But, since Islam does not neglect man's material need, part of the goal of Zakah al-Fitr is the economic well-being of the poorer members of society.
Zakah al-Fitr is only Wajib for a particular period of time. If one misses the time period without a good reason, he has sinned and cannot make it up. This form of charity becomes obligatory from sunset on the last day of fasting and remains obligatory until the beginning of Salah al-'Eid' (i.e. shortly after sunrise on the following day). However, it can be paid prior to the above mentioned period, as many of the Sahabah [companions of the Prophet (peace be upon him)] used to pay Sadaqah al-Fitr a couple days before the Eid. Nafi reported that the Prophet's companion Ibn Umar used to give it to those who would accept it and the people used to give it a day or two before the Eid. [Reported by al-Bukhari]
Ibn Umar reported that the Prophet (peace be upon him) order that it (Zakah al-Fitr) be given before people go to make the Salah (al-'Eid). And Ibn Abbas reported that the Prophet (peace be upon him) said, "Whoever gives it before the Salah will have it accepted as Zakah, while he who gives it after the Salah (will not, for it will only be considered as) ordinary charity."
« ...من أداها قبل الصلاة فهي زكاة مقبولة ومن أداها بعد الصلاة فهي صدقة من الصدقات»
Therefore, one who forgets to pay this Zakah al-Fitr on time should do so as soon as possible even though it will not be counted as Zakah al-Fitr.
The amount of Zakah is the same for everyone regardless of their different income brackets. The minimum amount is one Sa (two handfuls) of food, grain or dried fruit for each member of the family. This calculation is based on Ibn Umar's report that the Prophet (peace be upon him) made Zakah al-Fitr compulsory and payable by a Sa of dried dates or a Sa of barley. The Sahabi, Abu Said al-Khudri said, "In the Prophet's time, we used to give it (Zakah al-Fitr) as a Sa of food, dried dates, barley, raisins or dried cheese". [Reported by Al-Bukhari]