Sales Tax Calculator
Calculate sales tax and totals from a pre-tax price, or back out the pre-tax price from a tax-included total.
Enter a price and a tax rate to see the tax amount and final total instantly. Add an optional discount (percentage or flat) applied before tax to see your discounted subtotal, tax on that amount, and total savings. Switch to reverse mode to find the pre-tax price hidden inside a tax-included total.
Sales tax rates vary from 0% in states like Montana and Oregon to over 10% in parts of Louisiana and Tennessee once local taxes stack on top. Whether you are shopping, pricing a product, or reconciling a receipt, the math is a two-step process: apply the discount (if any) to get the taxable amount, then multiply by the rate. Getting the order wrong, for instance applying tax before the discount, overstates your total.
Reverse calculation matters just as often. A printed receipt shows the full amount you paid, but if you need to log the pre-tax price for expense reporting or bookkeeping, you divide the total by (1 + rate) rather than subtracting the rate directly. Subtracting 8% from an 8%-inclusive total gives the wrong answer because the 8% was calculated on the smaller base, not the full amount.
This tool handles both directions. Forward mode computes tax on the discounted subtotal, shows a savings line when a discount is active, and updates every result live as you type. Reverse mode takes any tax-inclusive total and the applicable rate, then splits it into the pre-tax portion and the tax portion with the formula shown for transparency.
- 1
Enter the price and tax rate
Type the pre-tax price and the applicable sales tax rate. The tax amount and total update immediately as you type.
- 2
Optionally add a discount
Choose a percentage off or a flat dollar amount. The discount applies before tax, so you see the taxable subtotal, tax on that amount, and total savings all at once.
- 3
Switch to reverse mode when needed
Enter a tax-included total and the rate to back out the pre-tax price and the exact tax portion. Useful for expense reports and bookkeeping.
Shopping budget check
Before checking out, confirm the final total including tax so you know if the purchase fits your budget.
Product pricing
Set a retail price by working backward from the tax-included total you want customers to pay.
Expense reporting
A receipt shows the full charged amount. Reverse mode extracts the pre-tax value for accurate expense entries.
Coupon and sale math
Apply a percentage or dollar-off coupon before tax and see the exact savings and final amount.
Does the discount apply before or after tax?
Before tax. Most jurisdictions tax the discounted price, not the original. This calculator subtracts the discount first, then applies the tax rate to the reduced subtotal.
How does reverse tax calculation work?
Divide the tax-inclusive total by (1 + rate/100). For example, $108.50 at 8.5% gives $108.50 / 1.085 = $100 pre-tax. Subtracting 8.5% directly gives the wrong answer.
What tax rate should I use?
Use the combined rate for your location: state rate plus any county or city add-ons. Your state's department of revenue website lists these. Rates change, so verify before filing or quoting a final price.
Is my data private?
Yes. All calculations run in your browser. No numbers you enter are sent to any server or stored outside your device.
Can I calculate tax on a price that already has a discount built in?
Yes. Enter the original price and use the discount field to subtract the markdown. The calculator taxes the resulting subtotal, matching how most point-of-sale systems work.