Sales Tax Calculator: Reverse & Add Tax (VAT)

Calculated using standard mathematical and industry formulas.

Calculate sales tax by multiplying pre-tax item price by the tax rate decimal: Tax Amount = Price × (Rate / 100). To extract pre-tax price from a total price including tax, divide total price by (1 + Rate / 100). A $100 item with 8.875% tax totals $108.88.

How to use this calculator?

  1. Enter the tag price or sticker price of the item.
  2. Enter the store discount percentage (e.g. 20% off sale).
  3. Enter your state or local sales tax rate percentage.
  4. Read your net savings, pre-tax discounted subtotal, sales tax total, and final checkout amount.

Formula & calculation method

Retail Discount & Sales Tax Formula

Tax Amount = Pre-Tax Price × (Rate / 100); Total Price = Pre-Tax Price + Tax Amount; Reverse Tax: Pre-Tax Price = Total Price / (1 + Rate / 100)

Original Price ≥ $0, Discount% between 0–100%, Tax% between 0–50%.

Step-by-step calculation example

Original $100.00, 20% discount, 8.25% tax → Subtotal: $80.00, Tax: $6.60, Final Total: $86.60 (Saved: $20.00).

Key insights to remember

How to interpret your results?

Combined State and Local Rates

US sales tax rates vary widely across municipalities because local county and city surtaxes are added on top of the baseline state rate.

Expert advice & guidance

💡 Shopping tip: When purchasing major items in the US, five states (Alaska, Delaware, Montana, New Hampshire, Oregon) levy zero statewide sales tax.

Frequently asked questions

How do you calculate sales tax on an item?
To calculate sales tax, convert the tax percentage into a decimal (e.g., 8.875% = 0.08875) and multiply it by the pre-tax item price: Sales Tax Amount = Pre-Tax Price × (Tax Rate / 100).
What is sales tax and how does it work?
Sales tax is a ad-valorem consumption tax collected by retailers at the point of sale on behalf of state and local municipal governments, based on a set percentage of the retail price.
Which US states have no sales tax?
Five US states do not levy a statewide sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon (the NOMAD states). However, local jurisdictions in Alaska may charge municipal taxes.
How to calculate tax backwards from total amount (reverse tax)?
To extract the pre-tax price from a total price including tax, divide the total price by 1 plus the tax rate decimal: Pre-Tax Amount = Total Price / (1 + Tax Rate / 100).

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