You can use Purchase Tax Rate for this purpose. The purchase tax is paid by the company on the expenses and is subtracted from the charge amount to avoid double-taxation for the client. CORE uses this rate to separate the actual cost and tax amount. If you create a vendor bill with a purchase tax on it, CORE deducts that tax from its income account. If you enter an amount instead of a percentage, CORE reverse calculates the percentage value.

Cost Amount = Net Cost Amount + Purchase Tax Rate

Cost with Purchase Tax = Amount without Purchase Tax / (1 + Purchase Tax Rate / 100)

For example, If you apply a purchase tax of 10% to a vendor bill of $100, CORE recalculates the expense amount to $96.36. To show the Purchase Tax Rate column on the Edit Vendor Bill screen, go to More > Show/ Hide Columns > Purchase Tax Rate.