How to calculate sales tax
Example: an $80 item with 7.25% sales tax costs $80 × 0.0725 = $5.80 in tax, so $85.80 in total.
Working backward: a receipt total of $107.25 at 7.25% came from $107.25 ÷ 1.0725 = $100.00 before tax. A common mistake is to take 7.25% off the total, which gives $99.47 and is wrong, because the tax was charged on the smaller price.
Finding your rate
In the U.S., sales tax is set by the state and often topped up by the county and city, so two stores a few miles apart can charge different rates. The rate printed on a receipt is the combined rate. If you only have the totals, use Find the rate: divide the total by the price before tax and subtract 1.
Most stores add tax after any discount, which is why the discount calculator asks for the tax rate last.
Frequently asked questions
How do I calculate sales tax backward from a total?
Divide the total by 1 plus the rate as a decimal. At 8% tax, a $54 total came from $54 ÷ 1.08 = $50, with $4 of tax.
How do I find the sales tax rate from a receipt?
Divide the total by the price before tax, subtract 1 and multiply by 100. $85.80 ÷ $80 = 1.0725, so the rate is 7.25%.
Is sales tax charged before or after a discount?
In most U.S. states, after. You pay tax on the price you actually pay, not the original price.
Was this calculator helpful?