Sales Tax Calculator
Sales tax on a $100 purchase at an 8% rate is $8.00, for a total of $108.00. Enter the amount and your tax rate, then choose whether to add tax to a price or remove tax from a total that already includes it. The calculator shows the pre-tax amount, the sales tax, and the final total.
Quick answer
Adding tax multiplies the price by the rate to find the tax, then adds it to the price.
What this tells you
- •Adding tax multiplies the price by the rate to find the tax, then adds it to the price.
- •Removing tax divides a tax-inclusive total by one plus the rate to find the pre-tax price.
- •The sales tax is the difference between the total and the pre-tax amount.
How to Use
- 1Enter the dollar amount.
- 2Enter your local sales tax rate as a percentage.
- 3Choose Add tax to a price or Remove tax from a tax-inclusive total.
- 4Click Calculate to see the pre-tax amount, sales tax, and total.
How It Works
Formula
Add tax: Sales Tax = Amount x Rate / 100, Total = Amount + Sales Tax
Remove tax: Pre-Tax = Amount / (1 + Rate / 100), Sales Tax = Amount - Pre-TaxAdding tax treats the entered amount as the pre-tax price and applies the rate to it. Removing tax treats the entered amount as a total that already includes tax, so it divides by one plus the rate to recover the original price and reports the tax as the difference.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Add 8% tax to a $100 purchase
Sales tax is 100 x 8 / 100 = $8.00. The total is 100 + 8 = $108.00, and the pre-tax amount stays $100.00.
Remove 8% tax from a $108 total
Pre-tax price is 108 / 1.08 = $100.00. The sales tax is 108 - 100 = $8.00, and the total is the $108.00 you started with.
Sales Tax on $100 by Rate
Sales tax and total for a $100 pre-tax purchase at common rates. These rates are generic examples, not figures for any specific state.
| Tax Rate | Sales Tax | Total |
|---|---|---|
| 5% | $5.00 | $105.00 |
| 6% | $6.00 | $106.00 |
| 7% | $7.00 | $107.00 |
| 8% | $8.00 | $108.00 |
| 9% | $9.00 | $109.00 |
| 10% | $10.00 | $110.00 |
Rates are generic examples. Look up your combined state, county, and city rate for an accurate figure.
Adding vs Removing Sales Tax
Adding sales tax starts from a price before tax. You multiply the price by the rate to find the tax, then add it on. This is what happens at the register when a listed price gets tax applied at checkout.
Removing sales tax, sometimes called reverse sales tax, starts from a total that already includes tax. To find the original price, you divide the total by one plus the rate as a decimal. For an 8% rate, divide by 1.08. The tax is the difference between the total and that pre-tax price.
Use the remove mode when a receipt only shows the final amount and you need the pre-tax figure for an expense report or bookkeeping. Use the add mode when you know a list price and want to see the out-the-door cost.
Common mistakes
- Entering the rate as a decimal like 0.08 instead of a percentage like 8
- Adding tax when the amount already includes it, which double counts the tax
- Using a single state rate when the combined local rate is higher
- Forgetting that some items, such as groceries or clothing, may be tax exempt