If you set up sales tax correctly using sales tax items, rates, and codes, and you've assigned taxable or non-taxable status to your customers and items, QuickBooks automatically charges and calculates sales tax on invoices, sales receipts, estimates, and other sales forms.
Here's how sales tax is used and calculated on a sales form:
The sales tax code, shown in the Tax column on the right of the sales form, is the one you assigned to the item for tracking its taxable status.
The Tax field, at the bottom of the line items, shows the sales tax item or sales tax group item you assigned to the customer. The sales tax rate associated with that sales tax item (or sales tax group item) is shown to the right, in parentheses. QuickBooks uses this sales tax rate to calculate the sales tax.
The Customer Tax Code, at the bottom of the sales form, indicates the taxable status you assigned to this customer. At the time of your sale, QuickBooks checks your records to see if the customer is taxable. If so, the line items are checked. All taxable line items
on the sale are totaled and multiplied by the rate of the sales tax item (or sales tax group item) you assigned to the customer. If you just Quick Added a new customer, QuickBooks uses the most common sales tax rate that you set up in your sales tax preferences.
However, special sales situations can arise where you might not want to automatically charge sales tax for a particular customer or item. For example, you might need to charge two different sales tax rates for items on the same sale. If this is the case, the following topics may resolve your particular sales tax issue.
Changing sales tax information for a specific sale
Sell to out-of-state customers
Special sales tax situations and needs