Sales Tax Calculator: Add or Remove Tax (Free)

Whether you are pricing a product, checking a receipt, or working out the pre-tax cost of a purchase, sales tax maths is quick to get wrong under pressure. This guide shows how to both add tax to a price and reverse it out of a total, with worked numbers. The Sales Tax Calculator does it instantly for any rate — sales tax, VAT or GST — free and in your browser, with no sign-up.

How sales tax is calculated

Sales tax is a percentage added to a price. The tax amount is the price times the rate, and the final total is the price plus that tax.

The formulas are:

• Tax amount = price times (rate / 100)
• Total = price + tax amount, or simply price times (1 + rate / 100)

For a 70 price at 8% tax, the tax is 70 times 0.08, which is 5.60, and the total is 75.60. The same logic applies whether the levy is called sales tax, VAT or GST.

How to use the Sales Tax Calculator

It works both directions:

1. Open the Sales Tax Calculator.
2. Enter the amount — a pre-tax price or a tax-inclusive total.
3. Enter your local tax rate as a percentage.
4. Choose whether to add tax or remove it.
5. Read the tax amount and the final or pre-tax price instantly.

Change any field and it recalculates live, so you can test different rates quickly.

Worked example: adding 8% to 70

You are selling an item for 70 before tax, and your rate is 8%.

Calculate the tax, then the total:

• Tax = 70 times 0.08 = 5.60
• Total = 70 + 5.60 = 75.60

So the customer pays 75.60, of which 5.60 is tax. To go the other way, the next section shows how to pull that 5.60 back out of a 75.60 receipt.

Reverse sales tax: removing tax from a total

If you only know the tax-inclusive total and need the pre-tax price, you cannot just subtract the rate — you divide.

The formula is:

• Pre-tax price = total / (1 + rate / 100)
• Tax amount = total minus pre-tax price

For a 75.60 total at 8%: 75.60 divided by 1.08 is 70, so the tax was 5.60. This reverse calculation is essential for expense reports and bookkeeping when receipts only show the final price.

Sales tax, VAT and GST

The maths is identical, but the names and rates differ by region. US sales tax varies widely by state and city. VAT (value-added tax) is common in Europe and often already included in the displayed price. GST applies in countries like Australia, Canada and India.

Always use your local rate, and check whether prices already include tax.

Tips and related tools

Stay accurate:

• US rates depend on state and often city or county — confirm the combined rate for your location.
• Some items are tax-exempt or taxed at a reduced rate; apply the correct one.
• For reverse calculations, divide by 1 plus the rate, never subtract the percentage from the total.

For country-specific GST, the GST Calculator is tailored to it, and the Discount Calculator handles sale prices. More are in the free calculators.

Is it private?

Yes. The Sales Tax Calculator runs entirely in your browser, so the prices and rates you enter are never uploaded or stored. There is no account and no tracking of your figures, and it works offline once loaded. Browse more free, private tools for everyday money tasks.