How it works
To add tax, enter the price and your combined sales tax rate. To find the price before tax from a receipt total, switch to Total with tax.
Backing tax out is not the same as subtracting the rate from the total. Because the tax was calculated on the smaller pre-tax price, you divide by (1 + rate) instead.
Sales tax rates vary by state, county and city, and some items such as groceries are taxed at different rates or exempt. Check your local rate before relying on the result.
Formula
Total = price × (1 + rate ÷ 100); price = total ÷ (1 + rate ÷ 100)
Questions people ask
How do I calculate the price before tax?
Divide the total by 1 plus the tax rate as a decimal. For $108 at 8%, that is 108 ÷ 1.08 = $100.
Why not just subtract 8% from the total?
That would take 8% of the larger, taxed amount. $108 minus 8% is $99.36, not the original $100.
What sales tax rate should I use?
Use the combined rate where the sale happens: state plus any county, city or district tax. Your state revenue department publishes lookup tools by address.