Use the rate that applies
Sales tax varies by location and product. Enter the rate for your transaction; this calculator does not look up tax rates.
Free sales tax calculator
Sales Tax Calculator
Add sales tax to a price or remove tax included in a total. Enter your own rate to estimate the taxable amount, tax, and final price.
Calculate one item or a quantity of items, apply an optional discount, and format the result in a supported currency. The calculator runs locally in your browser.
Add or remove taxOptional discounts
Calculator
Enter your price and tax rate
Select whether your price is before tax or already includes tax. Results update as you enter valid values.
How sales tax is calculated
Sales tax is calculated from the taxable amount and the rate that applies to the transaction.
Add tax
Subtotal = Unit Price × Quantity
Taxable Amount = Subtotal − Discount
Sales Tax = Taxable Amount × Rate ÷ 100
Total = Taxable Amount + Sales Tax
For example, $100 × 8% = $8 tax, for a total of $108 before any other charges.
Remove included tax
Pre-tax Amount = Tax-Inclusive Amount ÷ (1 + Rate ÷ 100)
Included Tax = Tax-Inclusive Amount − Pre-tax Amount
At 8%, $108 ÷ 1.08 = $100 pre-tax, so the included tax is $8. Multiplying $108 by 8% would incorrectly treat the tax-inclusive amount as the taxable base.
Quantity and discounts
Quantity multiplies the unit price to create one combined subtotal. The calculator rounds tax on that combined taxable subtotal rather than rounding tax separately for every item.
In Add tax mode, the discount reduces the pre-tax subtotal before tax. In Remove included tax mode, the discount reduces the tax-inclusive total before tax is extracted. Tax and discount treatment can vary by jurisdiction.
Why local tax can vary
Rates and taxable products can differ by country, state, province, city, seller, and product category. Some purchases also include more than one tax component or special exemptions.
Enter the rate that applies to your purchase. This tool does not detect your location or retrieve tax rates. A checkout total may differ because of local rules, delivery charges, discount treatment, or rounding.
Worked sales tax examples
These examples use an 8% tax rate and show the basic calculation before other charges.
Add tax to $100
- Pre-tax price
- $100.00
- Sales tax at 8%
- $8.00
- Total
- $108.00
Remove tax from $108
- Tax-inclusive total
- $108.00
- Pre-tax amount
- $100.00
- Tax included at 8%
- $8.00
Quantity of 3
Three items at $20 each create a $60 subtotal. At 8%, tax is $4.80 and the total is $64.80.
Discount before tax
A $10 discount on a $100 pre-tax subtotal leaves $90 taxable. At 8%, tax is $7.20 and the total is $97.20.
Frequently asked questions
How do I calculate sales tax?
Multiply the taxable amount by the sales tax rate divided by 100. For example, 8% tax on a $100 taxable subtotal is $8.
How do I add sales tax to a price?
Enter the pre-tax price and applicable rate in Add tax mode. The calculator applies any discount to the combined pre-tax subtotal, calculates tax on that taxable subtotal, then adds the tax.
How do I find the tax included in a total?
Divide the tax-inclusive total by 1 plus the tax rate as a decimal to find the pre-tax amount. Subtract that amount from the tax-inclusive total to find the included tax.
Why can’t I calculate included tax by multiplying the total by the tax rate?
The tax rate applies to the pre-tax amount, not to the tax-inclusive total. At 8%, a $108 tax-inclusive total contains $8 tax because $108 ÷ 1.08 = $100 and $108 − $100 = $8.
Can I calculate tax for multiple items?
Yes. Enter a unit price and quantity. The calculator multiplies them to get a combined subtotal and rounds sales tax once on the combined taxable subtotal. Actual item-level tax rules can differ.
How do discounts affect sales tax?
In Add tax mode, a discount reduces the pre-tax subtotal before tax is calculated. In Remove included tax mode, the discount is subtracted from the tax-inclusive total before the included tax is extracted. Tax treatment of discounts varies by jurisdiction.
Does the calculator know my local tax rate?
No. Enter the applicable rate yourself. Rates can vary by location, product, and transaction, and the calculator does not look up rates or use an API.
Does changing currency convert the amount?
No. Currency selection changes the symbol and number formatting only. It does not convert values or use an exchange rate.
Why might the final checkout total differ?
Local rules, product taxability, delivery charges, discount treatment, multiple tax components, and tax rounding methods can change the final amount at checkout.