In order to find out how much tax you are currently being charged, you will first need to find your invoices within your administrator console. If you are unsure of how to do this, please see this article: How do I view my invoices?
Once you've located your invoices, you'll be able to see the amount of tax you are being charged under your invoice subtotal.
Example invoice with tax listed:
Please note that the amount of tax Box is required to charge varies from state to state. If you have any questions, please feel free to submit a support case to our Billing Team.