In short: To add sales tax, multiply the price by (1 + rate): $100 at 8.25% is $108.25. To find the pre-tax price from a total, divide by (1 + rate): $108.25 ÷ 1.0825 = $100.
About Sales Tax Calculator
US sales tax is added at the register on top of the shelf price, while VAT and GST in Europe, the UK, Australia and elsewhere are usually already included in the displayed price. Either way, you sometimes need the other number: the total you will pay, or the net price and tax hidden inside a total for an expense report or invoice.
Adding tax multiplies the price by one plus the rate. Removing tax divides the total by one plus the rate — a common mistake is subtracting the rate from the total, which gives the wrong answer (20% off £120 is £96, but the pre-VAT price of £120 at 20% VAT is £100).
How to use Sales Tax Calculator
- Choose Add tax or Remove tax.
- Enter the price (or total) and the tax rate.
- Read the tax amount and the other figure.
Examples
$100 at 8.25% → tax $8.25, total $108.25.
£120 including 20% VAT → net £100, VAT £20.
Frequently asked questions
How do I calculate the price before tax?
Divide the total by (1 + rate as a decimal). With 7% tax: total ÷ 1.07.
Why not just subtract the percentage?
Because the tax was calculated on the smaller pre-tax price. Subtracting 20% from a VAT-inclusive total removes too much.
What is the sales tax rate where I live?
US rates combine state, county and city taxes and change often; check your state revenue department. VAT rates are set nationally.
Is tax applied before or after discounts?
Usually after: discount first, then tax on the discounted price. Use the Discount Calculator first if needed.
Updated November 2026 · Free, no signup · How we build and test tools