Reverse Sales Tax Calculator

On This Page

• One divisor does the work
• Two modes
• Divisors for common rates
• Receipts, worked
• Where the same math shows up
• Excel and QuickBooks
• How both modes are verified
• FAQ

One Divisor Does the Work

Tax was added as a percentage of the pre-tax price, so the total is pre-tax × 1.08 at 8%. Divide by the same 1.08 to undo it: a $108 receipt is $100 plus $8 of tax. The common mistake is dividing by the rate alone (0.08), which gives a meaningless $1,350. Multiplying the total by 8% is also wrong, because it gives $8.64 instead of $8.00.

Two Modes

• Find pre-tax price: enter the total and the rate to get the pre-tax price and the tax inside it.
• Find tax rate: enter the total and the pre-tax price, and it solves Rate = (Total − Pre-tax) ÷ Pre-tax × 100. That helps with itemized receipts that do not print the rate.

Set the currency to match your receipt; results update as you type.

Divisors for Common Rates

Use the combined rate where you bought: state plus county and city. The state base rate alone usually understates it.

Since 2013, Quebec charges QST on the price before GST, so the two rates simply add. In British Columbia, PST covers fewer items than GST, so check whether an item carried 5% or the full 12%.

Receipts, Worked

• New Jersey, $53.25: ÷ 1.06625 = $49.94 pre-tax and $3.31 tax. Check: $49.94 × 1.06625 = $53.25.
• Manhattan dinner, $87.48: ÷ 1.08875 = $80.35, so $7.13 was tax. A 20% tip on the pre-tax $80.35 is $16.07, against $17.50 on the full total.
• Ontario expense, CA$226: ÷ 1.13 = $200 plus $26 HST, which an HST-registered business can claim back as an input tax credit.
• A 9.5% combined rate, $65.18: ÷ 1.095 = $59.53, with $5.65 of tax.
• Hotel, rate unknown: $149.00 room, $168.92 total. $19.92 ÷ $149 × 100 = 13.37%. Lodging taxes stack state, county and city charges well above normal sales tax.

Where the Same Math Shows Up

Any tax-inclusive total splits the same way: VAT in the UK and Europe, GST in Australia, HST in Canada. The same idea also untangles a price rise that has nothing to do with tax. See how much of a tariff-driven price increase is really cost and the 60-country tariff round from July 2026. Grossing up works on pay as well: the Gross to Net Pay Calculator works back from a target paycheck to the salary behind it. To build tax-inclusive prices from a cost and margin in the first place, use the Product Pricing Calculator.

Excel and QuickBooks

In Excel, with the total in A1 and the rate as a number such as 8 in B1, the pre-tax price is =A1/(1+B1/100) and the tax is =A1-C1. For a whole column of receipts at one rate, lock the rate cell: =A2/(1+$B$1/100), then fill down.

QuickBooks has no "reverse tax" button. On a bill, choose the tax code and tick amounts are tax inclusive, and it splits the tax into the liability account for you. For inventory this matters, because recording the tax-inclusive amount overstates cost of goods sold. Report revenue from marketplace sales pre-tax too, then check margins with the Gross Profit Calculator or Profit Margin Calculator.

How Both Modes Are Verified

From Rate mode divides the tax-inclusive total by (1 plus tax rate ÷ 100) to isolate the pre-tax amount, then subtracts that pre-tax figure from the total to get the tax amount in dollars. From Pre-Tax mode runs the same two numbers in the other order: it subtracts your entered pre-tax price from the total first, then divides that difference by the pre-tax price to solve for the rate. A $54.74 total at an 8% rate returns a $50.69 pre-tax price under the first mode, and re-entering those same two numbers under the second mode returns 8% back out, confirming the two panels compute inverse directions of one relationship.

Frequently Asked Questions

Why should I tip on the pre-tax amount, not the total?

Tipping on the pre-tax amount is the standard convention because the tax is not part of the service. On a $87.48 NYC bill, the pre-tax food total is $80.35. A 20% tip on $80.35 = $16.07, versus 20% on $87.48 = $17.50. Both are acceptable, but tipping on the pre-tax is the traditional baseline, and restaurants that add automatic gratuity typically apply it to the pre-tax subtotal.

Is reverse sales tax the same as tax-inclusive pricing?

Yes, in effect. Tax-inclusive (or tax-inclusive pricing) means the quoted price already includes the tax. Reverse sales tax is the calculation that extracts the components from a tax-inclusive total. You are solving for the embedded price that, once tax is added, equals the amount the customer paid.

Can I use this for VAT in the UK or Europe?

Yes. The math is identical. UK standard VAT rate is 20%, divisor 1.20. Germany and France: 19% and 20% respectively. A £120 UK purchase at 20% VAT: £120 ÷ 1.20 = £100 net price, £20 VAT. Enter the VAT rate in the calculator just as you would a US sales tax rate. For businesses reclaiming input VAT, the net amount (£100) is the deductible cost, and the VAT amount (£20) is the reclaim on the return.

References

• State and Local Sales Tax Rates, Tax Foundation: authoritative annual table of state sales tax rates, average local rates, and combined rates by state.
• GST/HST for Businesses, Canada Revenue Agency: official CRA guidance on collecting, remitting, and recovering Canadian sales taxes including input tax credits.
• Basic Rules for Applying the GST/HST and QST, Revenu Québec: how GST and QST are each calculated on the pre-tax price in Quebec.