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Ezivo Calculator
Formula testedEveryday MoneyTechnical QA reviewed 28 October 2026

Sales Tax Calculator

Add or extract sales tax from a price and include quantity, discounts, shipping and an optional secondary rate.

Business & Shopping

Add or remove sales tax

Estimate checkout tax with quantity, discounts, shipping and an optional local tax rate.

Advanced options: discounts, shipping and local tax+
Taxability of products, discounts and shipping varies by location. Use the rates and treatment shown on the relevant official tax guidance or invoice.

Estimated checkout total

Enter required inputs

Methodology

How this calculator works

Quantity creates the merchandise subtotal. Percentage and fixed discounts reduce that subtotal. In tax-exclusive mode, entered rates are added to discounted merchandise and taxable shipping. In tax-inclusive mode, the combined rate is extracted from merchandise, while separately entered taxable shipping receives added tax.

Worked example

Reading the result

For a 100 pre-tax item at 8% tax, the tax is 8 and the total is 108. If 108 already includes 8% tax, simply multiplying by 8% would be wrong; dividing by 1.08 recovers the 100 net price.

Checkout guide

Match the invoice tax treatment

Confirm whether prices already include tax, whether discounts reduce the taxable amount and whether shipping is taxable. These rules vary across countries, states, provinces and product categories.

Result checks

Use the Sales Tax Calculator with confidence

  • Confirm the question: make sure the selected mode, units and time period match the everyday money decision you are trying to make. Similar-looking inputs can represent different quantities or baselines.
  • Inspect the breakdown: review intermediate values, assumptions and rounding before copying the final result. Re-enter the example or a simple known case when you need an independent reasonableness check.
  • Preserve the inputs: note the values and options used if the result will support a comparison or later calculation. Recalculate when an input changes, and use the scope section below to identify decisions that need an official standard or professional review.

Common questions

Frequently asked questions

How do I add sales tax to a price?+

Choose the before-tax mode. The calculator applies the combined entered tax rates to the discounted taxable price and taxable shipping.

How do I remove tax from an inclusive price?+

Choose tax-included mode. The tool divides the merchandise total by one plus the combined tax rate, then shows the included tax separately.

Are discounts applied before tax?+

This calculator applies entered discounts before tax. Actual coupon and rebate treatment can vary by jurisdiction.

Is shipping taxable?+

Rules differ. Use the shipping treatment selector to match the applicable local rule or invoice.

Testing and transparency

Method source and technical review

Source: the formula, assumptions and scope documented on this page. The calculator logic is covered by automated input, boundary and result checks, and external published standards are linked where relevant. Global tools do not assume a country-specific law, tax rate or current market rate unless the page explicitly says so.

Author: Ezivo Calculator · Reviewed by: Ezivo Calculator technical QA · Read our methodology and editorial policy.

Important scope

Rates and taxability must be entered by the user. The tool does not determine product exemptions, tax holidays, origin or destination sourcing, nexus, filing requirements or official rounding rules. Check the result against any applicable professional or official requirements. This calculator provides general information only, not financial, tax, medical, legal or professional advice.

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