Calculate sales tax and total price for any rate, or reverse-calculate the tax from a total.

About the Sales Tax Calculator

Whether you're a shopper checking a receipt, a freelancer quoting a client, or a bookkeeper reconciling a total, sales-tax math comes up constantly — and it runs in two directions. Sometimes you have a pre-tax price and need the final total; other times you have a total and need to back out the tax it contains. This calculator handles both with a single toggle.

In 'Add tax' mode you enter a pre-tax amount and a rate to get the tax and grand total. In 'Remove tax' mode you enter a tax-inclusive total and rate, and the tool extracts the original pre-tax price and the embedded tax — the calculation most people get wrong when they simply multiply the total by the rate.

How the Sales Tax Calculator works

Add-tax mode is direct: tax = amount × rate ÷ 100, and total = amount + tax. Remove-tax mode requires division because the tax is already baked in: pre-tax = total ÷ (1 + rate ÷ 100), then tax = total − pre-tax. This is the key insight — you cannot back out tax by multiplying the gross figure by the rate, because that overstates the tax.

The rate field accepts decimals so you can enter combined state-plus-local rates precisely, such as 8.25%. Results update live in three panels: pre-tax amount, sales tax, and total, so the relationship between the numbers is always visible.

Worked example

In add-tax mode with the defaults — $100 pre-tax at 8.25% — the tax is 100 × 0.0825 = $8.25 and the total is $108.25.

Switch to remove-tax mode with a $108.25 total at the same 8.25% rate: pre-tax = 108.25 ÷ 1.0825 = $100.00, and the embedded tax is $8.25. Note the contrast — naively taking 8.25% of $108.25 would give $8.93, overstating the tax by 68 cents, which is exactly the mistake this mode prevents.

Tips & common mistakes

Always use the combined rate. Sales tax is usually a stack of state, county, city, and special-district rates; entering only the state base understates the total in most localities.
Use remove-tax mode to separate tax from a gross receipt for bookkeeping. Recording the pre-tax sale and the tax liability correctly keeps your books and your sales-tax return in sync.
Remember that not every item is taxable. Groceries, prescription drugs, and some services are exempt in many states, so apply the calculator only to the taxable portion of a mixed sale.
For quotes, tell clients whether your figure is tax-inclusive or tax-exclusive up front — the toggle here mirrors that distinction and prevents billing disputes.

Sales Tax Calculator: frequently asked questions

How do I calculate the pre-tax price from a total?

Divide the total by 1 plus the rate as a decimal — for an 8.25% rate, divide by 1.0825. Do not multiply the total by the rate; because the tax is already inside the total, that method overstates it. Remove-tax mode does the division correctly for you.

What's the difference between add-tax and remove-tax mode?

Add-tax starts from a pre-tax figure and adds tax on top, which is how you price a sale. Remove-tax starts from a tax-inclusive total and works backward to find the original price and the tax portion, which is how you decompose a receipt or gross sales figure for accounting.

Why does my calculated tax differ from the store receipt by a penny?

Retailers round each line or the invoice total to the nearest cent, and rounding conventions vary. On a single item the difference is usually a penny or two. For reconciling books, small rounding gaps are normal; large gaps usually mean the rate or the taxable base is wrong.

Does this calculator know my local rate?

No — you enter the rate, which keeps it accurate for any jurisdiction. Look up your combined state and local rate using your state revenue department's address or ZIP lookup, then type it into the rate field. That way the tool works anywhere rather than relying on an outdated built-in table.

Can I use this for VAT or GST instead of U.S. sales tax?

The arithmetic is identical, so yes — enter your VAT or GST percentage in the rate field. The main practical difference is that VAT-inclusive pricing is the norm abroad, meaning remove-tax mode is the one you'll use most to find the net amount from a gross price.

Sales Tax Calculator