Sales tax math
To add tax: total = price × (1 + rate). To remove tax: pre-tax = total ÷ (1 + rate). Tax = total − pre-tax. A $50 item at 7% is $53.50. If a receipt shows $53.50 including 7%, the pre-tax price is $50.
US rates are set by state and often city or county. Look up the combined rate for the ZIP code if you are invoicing. This page does not pick a jurisdiction for you.
Common questions
Is this the same as GST/HST?
Same math, different rates. Canadians who want province presets should use the GST / HST page.
What if food is not taxed?
Enter 0 as the rate for that item, or only run the tool on the taxable part of the bill.