Sales Tax Calculator by State for Small Sellers
Free Business Tool
Sales Tax Calculator
Add sales tax to any amount — or work backwards from a tax-inclusive total to the pre-tax price. Any rate, instant. Free, no signup.
Your amount
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Invoice & Quote Generator
A real invoicing app in one offline HTML file — auto-adds tax, totals every line and exports a branded PDF. No subscription.
How to calculate sales tax
This free sales tax calculator does the math both ways. To add tax, it multiplies your amount by the tax rate and adds it on. To work backwards from a total that already includes tax, it divides by one plus the rate to find the original pre-tax price.
How do I add sales tax to a price?
Multiply the price by the tax rate as a decimal, then add it. For example, $100 at 8.25% is $100 × 0.0825 = $8.25 tax, for a $108.25 total. This calculator does it instantly for any rate.
How do I remove sales tax from a total?
Divide the tax-inclusive total by (1 + the rate). A $108.25 total at 8.25% is $108.25 ÷ 1.0825 = $100 before tax. The calculator shows this “reverse” figure too — handy for receipts and expense claims.
Adding tax to invoices?
If you bill clients, doing this by hand every time is slow. The Invoice & Quote Generator adds tax and totals automatically, and the Expense Tracker keeps your tax records straight.