Welcome to the Community. I'm here to provide you a little information about how Quickbooks calculate the sales tax rate.
There are three components that Quickbooks uses in calculating the sales tax rate. These are:
The state where you're registered to collect sales tax.
The physical address of your business.
The physical address listed on sales receipts or invoices.
The amount of sales tax you collect varies from state to state and location to location. Each state sets a sales tax rate. Counties, cities, other localities, and even special taxing districts can also set their own rates.
If you're into e-commerce and online business. You're most likely selling to customers in different states. Note that your tax situation will vary depending on what state you're located in and where you're selling. If you don't have a presence in a state, then you aren't required to collect sales taxes.