Is zakat calculated on the total borrowed amount, or on what remains after deducting the debt?

The debt is not deducted from zakat on money if the person owns other non-zakat-eligible assets that exceed his essential needs. However, if he does not have any such assets, or if he only owns a house he lives in and similar necessities that are indispensable, then the amount of the debt is deducted from the zakat-eligible money when the year (hawl) is completed, and the remainder is subject to zakat if it reaches the nisab.