Zakat al-Fitr is a duty incumbent on every Muslim. Ibn 'Umar reports: ‘Allah’s messenger made the Zakat al-Fitr, a sa' of dates or barley, binding on every Muslim: slave or free, male or female, young or old.
Zakat al-Fitr becomes due when the sun has set on the last day of Ramadan, because this is what signals the end of the fast. The time to pay it is divided into two parts: the preferable one and the acceptable one. The preferable time is from the break of dawn on the Eid day until shortly before the Eid prayer.