Quickly add sales tax to any price, or reverse a tax-included total back to its pre-tax amount. Works with any rate for shopping, quotes and accounting.
Add tax: total = price × (1 + rate%). Remove tax: base = total ÷ (1 + rate%). The remove step divides — it does not subtract the rate from the total, which understates the base.
Rates vary by state, county and city, and some items (food, clothing) are exempt. Knowing the included vs. excluded math keeps your books and reimbursements correct.
Using one national rate. A purchase crossing a city line can change the rate by a full point; enter the local rate for that sale.
Is sales tax the same as VAT? No. Sales tax is charged at the final sale; VAT is collected at each production step and usually included in the shelf price.
Do I owe tax on resale? Resellers typically use a exemption certificate; the end consumer pays the tax.