What is the ruling on paying Zakat on a debt, and what is its amount?

Allah Almighty has counted the indebted among the recipients of zakat, and this refers to the debtor who is entitled to what suffices to repay his debt, even if he possesses wealth that is insufficient for his debt. This is supported by what Muslim narrated from Abu Sa'id al-Khudri, that a man accumulated much debt, so the Prophet, peace and blessings be upon him, commanded the people to give him charity.