Sales Tax Calculator

Add sales tax to a price or remove sales tax from a total with this free sales tax calculator. Quickly calculate tax amount, subtotal, before-tax price, and final total for purchases and receipts.

Results

Subtotal
$0
Sales Tax Amount
$0
Final Total
$0
Before-Tax Price
$0
Discount Applied
$0
Per Item Total
$0

Enter your values and click Calculate to add or remove sales tax.

How this sales tax calculator works

This sales tax calculator helps you either add sales tax to a price or remove sales tax from a final total. It can also account for quantity and a flat discount before calculating the tax result.

Use it when shopping, reviewing receipts, estimating purchase totals, or finding the original before-tax price from a tax-included amount.

What to enter

  • Whether you want to add or remove sales tax
  • The original price or final total amount
  • Your sales tax rate
  • The quantity of items
  • Any discount amount to subtract
  • Your preferred rounding method

What the results mean

  • Subtotal: amount before tax after quantity and discount
  • Sales Tax Amount: tax charged on the taxable amount
  • Final Total: amount after tax
  • Before-Tax Price: original price before sales tax
  • Discount Applied: total discount used in the calculation
  • Per Item Total: average final cost per item

Sales tax calculator formula

When adding sales tax, the calculator uses:

Sales Tax = Subtotal × Tax Rate
Final Total = Subtotal + Sales Tax

When removing sales tax, it uses:

Before-Tax Price = Total ÷ (1 + Tax Rate)
Sales Tax = Total - Before-Tax Price

Tax rate should be entered as a percentage, such as 7 for 7%.

Tips for using a sales tax calculator

Know whether tax is already included

Some advertised totals already include tax, while most shelf prices do not. Choose the correct calculation type for accurate results.

Apply discounts before tax when appropriate

In many cases, discounts reduce the taxable amount first, though exact tax treatment may vary by jurisdiction and item type.

Use the right local rate

Sales tax can vary by city, county, and state, so using the correct rate makes the calculator more useful for real purchases.

Check per-item cost for bulk purchases

When buying more than one item, the per-item total can make it easier to compare real cost across options.

Frequently asked questions

How do I add sales tax to a price?

Multiply the price by the sales tax rate to find the tax amount, then add that tax to the original price.

How do I remove sales tax from a total?

Divide the tax-included total by 1 plus the tax rate as a decimal to find the before-tax price.

Does this calculator handle discounts?

Yes. This version includes a flat discount field so you can reduce the subtotal before calculating tax.

Are tax rules the same everywhere?

No. Actual sales tax rules can vary by location, product type, and whether discounts are taxed, so this calculator is best used as a general estimate.

Related finance calculators