To add sales tax, multiply the pre-tax price by the tax rate and then add that amount back to the original price. To remove sales tax, divide the total price by one plus the tax rate.
Adding tax to a sticker price
If an item costs $100 and sales tax is 8%, the tax is $8 and the total is $108. This is the direction most people use when budgeting for a purchase.
Quick example
Pre-tax price × tax rate = tax amount. Then pre-tax price + tax amount = final price.
Removing tax from a final total
If the total paid was $108 and the tax rate was 8%, divide $108 by 1.08 to get the original pre-tax amount. The difference between the total and the pre-tax number is the tax included.
Why this comes up often
- Comparing prices across locations with different tax rates
- Back-calculating expense receipts
- Estimating a budget before checkout
- Separating product cost from tax in reimbursements
Use the calculator next
Switch between add-tax and remove-tax mode depending on whether you are starting from the sticker price or the final receipt total.