I run my business and there is always some amount that has been given on credit and likewise I've taken some thing on credit, How should I pay the Zakah? Should I take all liabities and other things in account before deducting the Zakah? And can I also give Zakah in portions or should I take it out at one time.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The debts that you owe others make it non-obligatory on you to pay the Zakah on tradable goods.  Therefore, at the end of the whole year count all the tradable items that you possess and evaluate them according to their value in the market, then substract from this value the amount of debt, and then pay the Zakah in a lump sum without installments.

But if you have other valuable things on which Zakah is not obligatory and it is a surplus on your necessary needs like cars, building or effects and possessions that exceed your needs, then you have to pay the debts from this excess wealth, and then pay the Zakah on the whole remaining tradable goods.

However, do not pay the debt from what you need as cars to travel on or the like, or buildings to dwell in, or effects and possessions that you use, but rather take the debts from the value of tradable items only and pay the Zakah from what remains.

Allah knows best.