Reverse Sales Tax Calculator

Know the total price including tax? Use this free reverse sales tax calculator to instantly find the pre-tax price and the exact tax amount paid.

The final amount you paid or charged
e.g. 8 for 8% — check your state rate
Pre-tax price
Tax amount paid
Verification total
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How to Calculate Reverse Sales Tax

A reverse sales tax calculation works backwards from a tax-inclusive total to find the original pre-tax price. This is the opposite of the standard sales tax calculator, which starts with the pre-tax price and adds tax. Both tools use complementary formulas — knowing one gives you the other.

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

Step-by-Step Example

Total paid: $162.00  |  Tax rate: 8%

Step 1: Divisor = 1 + (8 ÷ 100) = 1.08
Step 2: Pre-tax price = $162.00 ÷ 1.08 = $150.00
Step 3: Tax amount = $162.00 − $150.00 = $12.00
Check: $150.00 × 1.08 = $162.00 ✓

The Most Common Mistake

Do not simply subtract the tax percentage from the total. Subtracting 8% from $162 gives $149.04 — which is wrong. The correct pre-tax price is $150.00. The error happens because 8% of $162 ($12.96) is not the same as 8% of $150 ($12). Tax is always calculated on the pre-tax price, so you must divide — not subtract — to reverse it correctly.

Reverse Sales Tax in Excel

Put the total price in A1 and the tax rate (e.g. 8 for 8%) in B1.
Pre-tax price: =A1/(1+B1/100)
Tax amount: =A1-A1/(1+B1/100)
These formulas work identically in Google Sheets. To apply across a column of totals, use =$B$1 as an absolute reference for the tax rate.

Reverse Sales Tax Examples

Click any example to load it into the calculator.

$108.00 total at 8%
$100.00
Tax paid: $8.00
$270.63 total at 8.25%
$250.00
Tax paid: $20.63
$160.50 total at 7%
$150.00
Tax paid: $10.50
$53.19 total at 6.625% (NJ)
$49.87
Tax paid: $3.32
$547.50 total at 9.5%
$500.00
Tax paid: $47.50
$1,000 total at 10.25% (Chicago)
$906.61
Tax paid: $93.39

Real-World Scenarios

Expense reporting: Your receipt shows a total of $86.40 for a business lunch in a city with 8% combined sales tax. Your expense form requires the pre-tax subtotal. Using the reverse sales tax calculator: $86.40 ÷ 1.08 = $80.00 pre-tax, with $6.40 in tax. This is the correct figure to enter on your expense claim.

Bookkeeping: A small business received $32,400 in total sales during the month, all subject to 8% sales tax. To record the revenue and tax payable separately: pre-tax revenue = $32,400 ÷ 1.08 = $30,000. Tax collected = $2,400. This needs to be remitted to the state. The sales tax calculator handles the forward version of this calculation for invoicing.

Pricing strategy: A retailer wants the all-inclusive price to be exactly $50.00, including 6.25% Texas state tax. To find the correct pre-tax price to list: $50.00 ÷ 1.0625 = $47.06 pre-tax. At 6.25% tax ($2.94), the total is exactly $50.00. Understanding this also connects to reverse percentage calculations — the same mathematical principle applies.

When to Use a Reverse Sales Tax Calculator

Expense Reports

Most expense policies require the pre-tax subtotal, not the receipt total. Use the reverse sales tax calculator to extract the correct figure from any tax-inclusive receipt quickly.

Bookkeeping & Accounting

Separate tax collected from net revenue in your accounts. When total sales figures include tax, dividing out the tax is essential for accurate profit and loss reporting and for calculating tax liability.

Invoice Verification

Check whether a supplier or platform charged the correct tax amount on an invoice. Enter the total and the applicable rate — if the pre-tax price matches the line item, the tax was calculated correctly.

Round-Total Pricing

Set prices so the customer pays a clean total. Work backwards from the target all-in price to find what pre-tax price you need to list. Particularly useful for retail and hospitality businesses.

Audit & Reconciliation

Reconcile reported sales against tax remitted. If total receipts and the tax rate are known, the pre-tax revenue and tax payable can be derived without needing access to the original pre-tax figures.

Consumer Verification

Verify that the tax shown on a receipt is correct. Divide the total by (1 + rate) and compare to the subtotal on the receipt. Any discrepancy may indicate a pricing error or the wrong tax rate being applied.

Frequently Asked Questions

How does a reverse sales tax calculator work?
A reverse sales tax calculator divides the tax-inclusive total by (1 + tax rate / 100) to find the pre-tax price. For example, a $108 total at 8% tax: $108 ÷ 1.08 = $100 pre-tax. The tax paid is $108 − $100 = $8. Enter your total and rate above for instant results with full step-by-step working.
What is the reverse sales tax formula?
Pre-tax Price = Total ÷ (1 + Tax Rate ÷ 100). Tax Amount = Total − Pre-tax Price. Example: total = $215, tax rate = 7.5%: Pre-tax = $215 ÷ 1.075 = $200.00. Tax = $15.00. This is also called "backing out" the tax or "stripping" the tax from the total.
Why can't I just subtract the tax percentage from the total?
Because the tax rate is applied to the pre-tax price, not the total. Subtracting 8% from $108 gives $99.36 — wrong. The correct answer is $100. The difference: 8% of $100 = $8 (correct tax), but 8% of $108 = $8.64 (what you subtracted). Always divide by (1 + rate/100) to correctly calculate reverse sales tax.
How do I calculate reverse sales tax in Excel?
Put the total in A1 and the tax rate (e.g. 8 for 8%) in B1. Pre-tax price: =A1/(1+B1/100). Tax amount: =A1-A1/(1+B1/100). Format as currency. To apply to a column, use =A2/(1+$B$1/100) dragged down. Works identically in Google Sheets.
How is the reverse sales tax calculator different from the regular sales tax calculator?
The regular sales tax calculator starts with the pre-tax price and adds tax: Total = Price × (1 + Rate/100). The reverse sales tax calculator starts with the total and removes the tax: Pre-tax = Total ÷ (1 + Rate/100). They are inverse operations. Use the forward version when invoicing or pricing; use the reverse version when analysing receipts or bookkeeping.
How do I find the tax rate from a total and pre-tax price?
If you know both the pre-tax price and the total, derive the rate with: Tax Rate = (Total ÷ Pre-tax Price − 1) × 100. Example: pre-tax = $80, total = $86.40: rate = (86.40/80 − 1) × 100 = 8%. If you only know the tax amount and pre-tax price: Tax Rate = (Tax Amount ÷ Pre-tax Price) × 100.
What does "back out sales tax" mean?
"Back out sales tax" means removing the tax component from a tax-inclusive total to recover the original pre-tax price. It is the same as a reverse sales tax calculation. Accountants, bookkeepers, and business owners frequently need to back out sales tax from receipts, invoices, and revenue totals.
Can I use a reverse sales tax calculator for VAT?
Yes — the formula is identical. VAT is also calculated on the pre-tax price and included in the displayed price in most countries. The reverse formula Pre-tax = Total ÷ (1 + Rate/100) works for any tax that is a percentage of the pre-tax amount, whether it is US sales tax, UK VAT, EU VAT, Canadian GST, or Australian GST.

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