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Everyday Finance

Sales Tax Calculator

Calculate sales tax and the final after-tax price, or reverse tax from a tax-inclusive total.

Best for: Add sales tax to a pre-tax price or extract tax from a tax-inclusive total using a chosen rate.

Your assumptions

Calculate your estimate

Your result

Sales Tax estimate

Total including tax
$108.25
Tax amount
$8.25
Pre-tax price
$100.00

How to use this sales tax calculator

Use this sales tax calculator to move between pre-tax price, tax amount, and final total. The arithmetic is transparent, but the correct rate and taxable base depend on jurisdiction, product, exemptions, and sourcing rules.

  1. 1

    Choose add-tax or reverse-tax use

    Identify whether the entered amount excludes tax or already includes it.

  2. 2

    Enter price and applicable rate

    Use the combined rate for the actual location and transaction.

  3. 3

    Verify the taxable base

    Check whether shipping, services, discounts, or specific items receive different treatment.

Worked planning example

Example: reverse tax from a receipt total

Set up

Enter the tax-inclusive receipt amount and the applicable sales-tax rate.

Compare

Compare the extracted tax with the receipt and check for exempt or differently taxed items.

Takeaway

Reverse calculation works only when one tax rate applies to the entire entered amount.

Confirm jurisdiction and product treatment

This tool calculates entered numbers; it does not determine taxability or filing obligations.

  • Use the transaction-location rate.
  • Check exemptions and tax holidays.
  • Keep invoice-level records for compliance.

Calculation methodology and assumptions

For this sales tax estimate, Silvia uses calculation direction, entered price, sales tax rate. Calculate sales tax and the final after-tax price, or reverse tax from a tax-inclusive total. Results are estimates, not quotes, tax advice, or investment recommendations.

Frequently asked questions

How do I add sales tax?

Multiply the pre-tax price by the rate to find tax, then add it to the price.

How do I remove tax from a total?

Divide the tax-inclusive total by one plus the tax rate expressed as a decimal.

Does the calculator know my local tax rate?

No. Enter the applicable state, local, or combined rate after verifying it with the relevant authority.

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