Reference: Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa – Volume 23, Page 16, Question No.2 of Fatwa No.10711
Question: Regarding the expiation of an oath, what is the [required] amount for feeding a poor and destitute person? And is it permissible to give the total amount of food required to feed ten poor and destitute people, to a single poor and destitute person only?
Response: Regarding the expiation of an oath, the [required] amount for feeding a poor and destitute person is half a saa’ of wheat or rice, or that which is similar from the staple diet of the land; And this [amount] equates to approximately 1.5 kilograms. And it is not permissible to give the food required to feed ten [people] to one [person], rather, [feeding] ten [poor and destitute people] is a requirement; This is based upon the statement of Allaah:
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet Muhammad (sal-Allaahu `alayhi wa sallam) and his family and his companions.