Free Tool

Reverse Sales Tax Calculator

Enter a tax-inclusive total and tax rate to instantly find the pre-tax price and tax amount. Also works as a forward tax calculator.

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Enter an amount and tax rate above to see your results.

About Reverse Sales Tax Calculator

About This Reverse Sales Tax Calculator

This free tool lets you remove tax from a tax-inclusive total — or add tax to a net price — in one click. Enter the gross amount and the applicable rate (VAT, GST, HST, or US sales tax) and instantly see the pre-tax price, tax amount, and effective tax rate.

The Reverse Sales Tax Formula

Pre-tax Price = Total ÷ (1 + Rate ÷ 100)

Tax Amount = Total − Pre-tax Price

Effective Rate = Tax Amount ÷ Total × 100

Worked Example — Reverse (Remove Tax)

A receipt shows €242. The applicable VAT rate is 21%:

  • Pre-tax Price = €242 ÷ 1.21 = €200.00
  • Tax Amount = €242 − €200 = €42.00
  • Effective Rate = €42 ÷ €242 × 100 = 17.36% of total

The Forward Tax Formula

Total Price = Net Price × (1 + Rate ÷ 100)

Tax Amount = Total Price − Net Price

Common Tax Rates by Country

  • 5% — Canada GST, some US states
  • 10% — Australia GST, Japan consumption tax
  • 15% — New Zealand GST, some Canadian provinces (HST)
  • 20% — UK VAT, France VAT, Austria VAT
  • 21% — Netherlands VAT, Belgium VAT, Spain VAT
  • 25% — Denmark VAT, Sweden VAT, Norway VAT

Why the Tax Is a Smaller Share of the Total

A 20% tax rate does not mean 20% of the gross total is tax. Because the rate is applied to the net price, tax is always a smaller share of the gross. For 20% VAT, tax is only 16.67% of the total (1/6th). This is why you cannot simply multiply the total by the tax rate — you must use the reverse formula to get the correct split.

Got questions?

Frequently Asked Questions

Everything you need to know about our tools. Can't find what you're looking for? Contact us.

What is a reverse sales tax calculation?

A reverse sales tax calculation works backwards from a tax-inclusive total to find the original pre-tax price. Instead of adding tax to a price, you divide the total by (1 + tax rate) to extract the base price and the tax amount that was included.

What is the formula to reverse sales tax?

Pre-tax Price = Total Price ÷ (1 + Tax Rate ÷ 100). Tax Amount = Total Price − Pre-tax Price. For example, a €121 total with 21% VAT → Pre-tax = €121 ÷ 1.21 = €100. Tax = €121 − €100 = €21.

When would I need to remove tax from a total?

Common scenarios include: extracting VAT from a receipt for expense reporting, calculating net revenue from gross sales, working out input VAT for reclaim purposes, verifying a supplier invoice, or converting a consumer price to a wholesale/trade price.

What is the difference between reverse and forward tax calculation?

Forward: you start with a net (pre-tax) price and add tax — Total = Price × (1 + Rate%). Reverse: you start with a gross (tax-inclusive) total and extract the tax — Pre-tax = Total ÷ (1 + Rate%). Both are covered by this calculator using the mode toggle.

Why can't I just multiply the total by the tax rate to get the tax amount?

That gives the wrong answer because the tax rate applies to the pre-tax price, not the gross total. For example, 20% of €120 = €24 (incorrect). The correct method: €120 ÷ 1.20 = €100 pre-tax, €120 − €100 = €20 tax. The tax is always a smaller share of the total than the headline rate.

What does "effective tax as % of total" mean?

This is the tax amount expressed as a percentage of the gross (tax-inclusive) total. It is always lower than the nominal tax rate. For 20% VAT the effective rate is 16.67% of the total (€20 out of every €120). This figure is useful for reconciling receipts and VAT returns.

Does this calculator work for VAT, GST, and HST?

Yes. VAT (EU), GST (Australia, Canada, New Zealand), HST (Canada), and US state sales tax all follow the same mathematical formula. Simply enter the applicable rate for your country or jurisdiction.