Home › Free Tools › Sales Tax Calculator (Add or Reverse Tax, Any State Rate)
Add sales tax to a price, or run it in reverse — work backwards from a tax-included total to find the tax inside it. Enter your state or local rate for instant results.
Sales tax trips up a lot of small business owners because it works in two directions. Sometimes you have a pre-tax price and need to add tax to it. Other times you have a total that already includes tax and need to figure out how much of it was tax — for example when you’re reconciling a cash sale or filling out a return. This free calculator does both.
To add tax, enter the net (pre-tax) amount and your tax rate, and it shows the tax and the final gross price. To reverse it, switch to “Extract tax from total,” enter the gross amount and the rate, and it splits the total back into net and tax. The math updates the moment you type, so there’s nothing to submit and no signup.
The formulas are simple: to add tax, gross = net × (1 + rate ÷ 100). To extract tax from a tax-inclusive total, net = gross ÷ (1 + rate ÷ 100), and tax = gross − net. Knowing the reverse calculation is handy any time a receipt shows only the total.
Worked example, both directions. Backing tax out: a receipt shows a $107.50 total in a 7.5% area — divide by 1.075 to get the $100.00 pre-tax price, so $7.50 of the total was tax. A common mistake is multiplying the total by 7.5% instead ($8.06), which overstates the tax because the rate applies to the net, not the gross. Grossing up works the other way: if you need to walk away with $500 after collecting 6% tax, charge $530.00 (500 × 1.06) — the extract mode confirms $530 splits back into $500 net and $30 tax.
If you invoice customers, StandupCRM applies the right tax automatically on every sale and keeps a running record for filing — but for a quick one-off check, this tool has you covered.
Multiply the price by the tax rate (as a decimal) and add it to the price. This tool does it automatically — enter the amount and rate.
Divide the total by (1 + rate/100) to get the net, then subtract to get the tax. Use the “Extract tax from total” mode.
Divide the tax-included total by (1 + rate ÷ 100). A $107.50 total at 7.5% backs out to $100.00 net and $7.50 tax. Don’t multiply the total by the rate — that overstates the tax.
Multiply the amount you want to keep by (1 + rate ÷ 100). To net $500 at a 6% rate, charge $530. Use the add mode with your target amount as the pre-tax price.
Yes, completely free with no signup.
No. The calculation runs in your browser and nothing is sent anywhere.
StandupCRM gives repair shops Google Ads landing pages, lead capture, and a CRM dashboard — plus free tools like this to bring customers in.
See a live demo →