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Sales Tax Calculator

Add sales tax to a price or work backward from a tax-inclusive total.

Your numbers

Make it your own
Updates as you type
Total including tax
$108.00

USD · rounded to the nearest cent

Sales tax$8.00
Before tax$100.00
Tax rate8%

Enter your applicable combined rate. No live state or local tax rates are supplied. Taxability, exemptions, and jurisdiction rules may change the actual tax.

Your calculation, step by step

No black boxes
  1. Tax = 100 × 8/100 = 8 USD.
  2. Total = 108 USD.

What if things were different?

Save up to three scenarios, then change your inputs to compare the possibilities.

How to use this calculator

  1. Enter your own values in the labeled fields. Check the units and assumptions before comparing results. Only the fields needed for your selected calculation mode are shown.
  2. Your answer updates automatically. Review the calculation steps to see exactly how it was calculated.
  3. Copy, share, save, or download your result. Saved inputs stay on this device.

How the calculation works

Tax = price × rate; tax-exclusive price = total / (1 + rate)

Adding tax multiplies a taxable price by the entered rate. Removing tax divides the inclusive total by one plus the rate, rather than subtracting the rate from the total. This calculator does not look up current jurisdiction rules or decide whether a product is taxable.

A worked example

$100 before tax at 8% becomes $108. Removing 8% included tax from $108 returns $100.

Reading your result

Use the main result together with its units and supporting figures. Display values are rounded; calculations keep their underlying precision. A change in inputs or assumptions can change the answer. Compare the step-by-step working with your intended use before relying on an estimate.

Frequently asked questions

Are local rates loaded automatically?

No. Enter a rate verified for your transaction and jurisdiction.

Does this calculate business income tax?

No. It is a simple sales-tax arithmetic tool.

Sources & methodology

This calculator uses the mathematical identity and assumptions stated above. No current rates, prices, or external data are loaded. Conversion tools use international unit definitions.

Formula review: October 24, 2026. Read our methodology.