Sales Tax Calculator

Use this sales tax calculator to estimate the tax amount and total price from a pre-tax price and a combined sales tax rate. It is useful for shopping, invoices, budgeting, and checking receipt math.

How to use this calculator

Enter the price before tax and the sales tax rate. Use the combined state and local rate for the purchase location when available. The calculator returns total with tax, tax amount, rate, and subtotal.

Formula

Sales tax is calculated as:

Sales tax = pre-tax price × tax rate
Total price = pre-tax price + sales tax

To reverse sales tax from a tax-included total by hand:

Pre-tax price = total price / (1 + tax rate)

The form uses the first two formulas. For example, a 75 dollar purchase with an 8 percent sales tax adds 6 dollars of tax, for an 81 dollar total.

Shopping context

Sales tax can vary by state, county, city, item type, exemptions, holidays, marketplace rules, and shipping treatment. If a discount applies first, calculate the tax on the discounted price. You can estimate discounts with the percent off calculator, compare unit prices with the price per unit calculator, or split service bills with the tip calculator.

Limitations

This calculator is for general estimates. It does not determine taxability, filing obligations, exemptions, or compliance rules.

Frequently asked questions

How do I calculate sales tax?

Multiply the price before tax by the sales tax rate. Add the tax amount to the price to get the total.

What rate should I enter?

Enter the combined state and local sales tax rate for the purchase location, such as 8.25 for 8.25%.

Does this calculator reverse tax from a tax-included total?

No. The form estimates tax from a price before tax and a sales tax rate.

Should sales tax be calculated before or after a discount?

In many shopping situations tax is applied after eligible discounts, but rules can vary by location and product type.