How is the Zakat on money calculated for business capital (debtor and creditor), and is Zakat due on the profits of a commercial store that is owned, or on the core capital?

At the end of the hawl (one lunar year), you must appraise your cash liquidity and trade goods at market price, and estimate the debts you hope to collect from people. Then, subtract the debts you owe, because debt prevents the obligation of zakat on trade goods. If you have surplus money beyond your basic needs that is not subject to zakat, use it to offset the debt so that your zakat-liable funds are spared. If these non-zakat funds are sufficient to repay the debt, then zakat becomes obligatory on the invested amount. If there are no other funds, then you owe no zakat if what remains after deducting the debt does not reach the nisab, which is equivalent to 85 grams of gold or 595 grams of silver.