Free sales tax calculator
Enter a price and your local tax rate to find the tax amount and total cost. The optional discount field applies the markdown before tax, just like stores do.
Tax amount
$—
Total (with tax)
$—
Effective tax rate
—%
How it works
Tax = price × (rate ÷ 100)
Total = price + tax
If you enter a discount, it applies first:
- Discounted price = price × (1 − discount% ÷ 100)
- Tax = discounted price × (rate ÷ 100)
- Total = discounted price + tax
Worked example
A $100 item at 8% tax with a 20% discount:
- After discount: 100 × 0.80 = $80
- Tax: 80 × 0.08 = $6.40
- Total: 80 + 6.40 = $86.40
Notes
US sales tax rates vary by state, county, and city. Most states apply sales tax after discounts, not before — this calculator follows that convention. Some states exempt certain goods (groceries, clothing) from sales tax entirely.
Frequently asked
How is sales tax calculated?
Tax = price × (rate ÷ 100). The total is price + tax. If a discount applies, the discount reduces the price first, then tax is applied to the discounted amount.
What is the effective tax rate?
When a discount is applied, the effective tax rate is the tax as a percentage of the original undiscounted price — always less than the nominal rate.
Does this include local and state tax?
The calculator takes whatever combined rate you enter. Look up your state + city + county combined rate on your state's revenue website and enter it as one number.
How do I reverse-calculate price from total?
Pre-tax price = total ÷ (1 + rate/100). For example, if the total is $108 at 8% tax: 108 ÷ 1.08 = $100.
How do I share my calculation?
Click "Share with my numbers" to copy a URL that restores your price and rate.