The Equivalent of the Prophet's Sa' in Handfuls
Question :
The Sa' of the Messenger of Allah, what is its equivalent in handfuls?
Answer:
What has been made evident to us regarding the Prophet's Sa is that it is equivalent to four scoops of the average-sized man's two hands, if they are full. This is what some of the scholars, such as the compilers of An-Nihayah and Al-Qamus have said.
As for the scoops which are present in the markets, they differ from each other, therefore the basic measure is what the scholars have mentioned, which is to measure by an average- sized man's two handfuls.
And Allah knows best.
Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 6 Page 362