Sales Tax Calculator

Sales tax works in two directions, and this calculator handles both: add tax to a pre-tax price to find the total you'll pay at the register, or back the tax out of a known total to recover the pre-tax price: handy for expense reports and bookkeeping, or for splitting a restaurant check once the tip calculator adds its share.

How does this calculator work?

Choose whether to add sales tax to a price or back it out of a total, then enter the amount and the tax rate. The calculator shows the pre-tax price, the tax, and the total.

Worked example

Adding 7.25% sales tax to a $100 item, then backing it out of a $107.25 total.

Pre-tax price

$100.00

Sales tax (7.25%)

$7.25

Total

$107.25

Back out: $107.25 ÷ 1.0725

$100.00

How the numbers work

Adding tax multiplies the price by 1 plus the rate: $100 × 1.0725 = $107.25, of which $7.25 is the tax.

Removing it reverses the operation: divide by the same factor, so $107.25 ÷ 1.0725 = $100.00. The common mistake is to subtract 7.25% of the total instead ($107.25 × 0.0725 = $7.78), which gives $99.47 and understates the true pre-tax price.

Adding tax multiplies by 1 plus the rate; removing it divides by the same factor. A common mistake is to subtract 7.25% from the total, which undershoots the true pre-tax price.