How to Calculate Sales Tax (Simple Formula + Calculator)

Whether you're pricing a product, checking a receipt, or budgeting a purchase, working out sales tax is a two-second calculation once you know the formula. Here's how to calculate sales tax.

The sales tax formula

Sales tax = price × (rate ÷ 100), and the total = price + tax. A $100 item at 8.5% tax adds $8.50, for a $108.50 total. The sales tax calculator gives you the tax, subtotal and total instantly.

Working backwards from a total

To find the pre-tax price from a tax-inclusive total, divide by (1 + rate). A $108.50 total at 8.5% came from $108.50 ÷ 1.085 = $100. Handy when a receipt only shows the final amount.

Sales tax vs VAT vs GST

They're similar ideas with different mechanics. US-style sales tax is added at checkout; VAT and India's GST are often included in the displayed price. For those, use the VAT calculator or the GST calculator, which has add and remove modes.

Watch the rate

Sales tax rates vary by state, county and even city, and some items are exempt. Always use the rate that applies where the sale happens, not where you live.

Related tools

Applying a coupon too? Use the discount calculator, and split the bill with the tip calculator.