QuickBooks has four item types that perform calculations on the amounts of a sales form. If you want to perform any of these calculations, you must have an item for each calculation you need.
| Type | Use when calculating |
|---|---|
| Subtotal | A subtotal. You must use a subtotal item before calculating a discount or a charge that covers several items. |
| Discount | An amount to be subtracted from the total. If you are applying the discount to more than one item, you must first use a subtotal item and then apply the discount to the subtotal. |
| Payment | Partial payment you receive at the time you write an invoice. A payment item reduces the amount owed on an invoice. |
| Sales tax | The tax that QuickBooks calculates in the Tax field on sales forms. (QuickBooks also uses this field to calculate non-taxable sales for the sales tax liability report.) |