the Prophet sent a caller in the roads of Makkah proclaiming "Sadaqatul-Fitr is required upon every Muslim, male or female, free or slave, young or old; it is two Mudd of wheat or its equivalent of a Sa of food."
Jami` at-Tirmidhi Book 7, Hadith 58
← Previous Hadith "We would give Zakat Al-Fitr - when the Messenger of Allah was among us - as a Sa of food, or a Sa of barely, or a Sa of dried dates, or a Sa of raisins, or a Sa of cheese. So we did not stop paying it (like that) until Mu'awiyah arrived in Al-Madinah and talked (about it). Among the things he addressed the people with, he said: 'I see that two Mudd of the wheat of Ash-Sham are equal to a Sa of dried dates.' So the people followed that." Abu Sa'eed said: "I will not stop giving it in the manner that I had been giving it."

Jami` at-Tirmidhi Book 7, Hadith 57 Next Hadith → "The Messenger of Allah made Sadaqatul-Fitr an obligation upon the male and female, the free and the bondsmen, as a Sa of dried dates or a Sa of barley." He said: "So the people equated that to half a Sa of wheat."

Jami` at-Tirmidhi Book 7, Hadith 59