- 2026 Edition · UK & US
Reverse sales tax calculator Find the pre-tax price from any receipt
If your receipt shows a total with tax already added, this reverse sales tax calculator finds the original price and exact tax amount in seconds — enter what you paid, set the rate, and it works backwards. This works the same whether the total is from a store receipt or a client invoice. Getting this wrong on an expense report means claiming the wrong amount; getting it right means your reimbursement matches the penny. Below, you’ll find the calculator, the formula explained in plain English, worked examples for US receipts and UK VAT returns, and a quick reference for common tax rates across states and currencies.
The formula behind the calculator
Reverse Sales Tax Calculator
Enter the total you paid (tax included) to find the original pre-tax price and exact tax amount.
What Is the Reverse Sales Tax Calculator?
A reverse sales tax calculator — sometimes searched as a sales tax reverse calculator — takes a price that already includes tax — the final total you see on a receipt or invoice — and works backwards to tell you two things: the original pre-tax price and the exact tax amount that was charged.
It’s built for three kinds of people. Receipt checkers who want to verify that a retailer applied the right rate. Small business owners and freelancers who need to separate the net amount from VAT or GST for bookkeeping. And online shoppers who spot a tax charge that looks off and want to check the math.
To use it, you need the total you actually paid (tax included), the tax rate that was applied, and the currency. The calculator supports USD, GBP, EUR, JPY, INR, PKR, CAD, and AUD. You can also label the tax — Sales Tax, VAT, GST, HST — so the breakdown output matches your invoice or accounting system.
How to Use the Reverse Sales Tax Calculator
1. Enter the total price (tax included). This is the final amount from your receipt or invoice — the number that already has tax built in. Use the stepper buttons or type directly. For USD, GBP, EUR, CAD, and AUD, amounts adjust in increments of 10; for JPY, PKR, and INR, they adjust in 100s, reflecting typical denomination sizes. This is also how to calculate price before tax from any receipt: enter the total once, and the pre-tax figure follows automatically.
2. Select your currency. Choose from USD, GBP, EUR, JPY, INR, PKR, CAD, or AUD. This controls how the result is formatted — JPY and PKR display as whole numbers; all others show two decimal places.
3. Set the sales tax rate. Drag the slider, click the +/− buttons, or type the rate directly into the rate field. The slider and numeric input stay in sync. The field accepts 0–30% in 0.5% increments. If you’re not sure what rate applies to your purchase, see the quick reference below.
4. Add a tax label (optional). Type “VAT,” “GST,” “Sales Tax,” or whatever label matches your receipt. This appears in the breakdown table — useful if you’re exporting the result for accounting software.
5. Click “Calculate pre-tax price →”. The calculator instantly shows the pre-tax price, tax charged, and a breakdown (pre-tax + tax = the total you entered). The result panel also confirms the rate applied and adds a short explanation of the math — including a note if you entered 0%, since no tax was charged in that case.
Once you have your result, use the “Copy results” button to copy a formatted summary to your clipboard, or “Export CSV” to download a file you can open directly in Excel, QuickBooks, or FreshBooks.
What Is the Formula for Reverse Sales Tax?
To find the pre-tax price, divide the total amount paid (including tax) by 1 plus the tax rate expressed as a decimal. For example, if you paid $107.50 with 7.5% sales tax applied: $107.50 ÷ 1.075 = $100.00 pre-tax. The tax amount is the difference: $107.50 − $100.00 = $7.50.
The formula written out: Pre-tax price = Total ÷ (1 + rate/100). That’s it. For a 20% VAT rate, you divide by 1.20. For an 8.875% New York City combined rate, you divide by 1.08875. The calculator does this instantly for any rate between 0% and 30%.
Here’s the detail that trips most people up: the tax as a percentage of what you actually paid will always be lower than the tax rate you entered. At a 10% rate, only 9.09% of the total is tax — not 10%. Why? Because the rate is applied to the pre-tax price, not to the total. If an item costs $100 and tax is 10%, you pay $110. The $10 tax is 10% of the base price but only 9.09% of the $110 you handed over. This is mathematically correct. If the “tax as % of total” column in the breakdown looks low, it’s supposed to.
This is also why subtracting the rate percentage from the total doesn’t work — it isn’t the same operation as dividing by 1 plus the rate. Subtracting 10% of $110 gives you $99 — not $100. The division method is the only correct approach, and it’s what this calculator uses.
US Sales Tax and UK VAT: What Rate Should You Enter?
The right rate to enter depends on where and what you bought. Here’s a jurisdiction-specific guide.
United States — Sales Tax
There is no federal sales tax in the US. Every state sets its own rate, and local governments can add on top of that. As of 2026, 45 states and Washington, D.C. collect a statewide sales tax. Five states collect none: Oregon, Montana, New Hampshire, Delaware, and Alaska — though Alaska allows municipalities to levy local rates.
What matters here is the combined rate — state plus local — since that’s the number that actually shows up on your receipt. According to Tax Foundation January 2026 data, the highest average combined rates are in Tennessee and Louisiana, both approximately 9.55%. California’s state rate of 7.25% is the highest in the US, with common combined rates of 8.25%–10.25% depending on county and city. Colorado’s state rate is 2.9%, but combined rates in major cities frequently exceed 8%. You can check your state’s current combined rate directly at the Tax Foundation’s state sales tax data.
Most states exempt unprepared groceries and prescription drugs. Four states — Alabama, Idaho, Mississippi, and South Dakota — tax groceries at the full rate. Tennessee applies a reduced 4% rate to groceries. Illinois eliminated its 1% state food sales tax effective January 1, 2026. Check your state Department of Revenue’s official site to verify the current rate before entering one.
United Kingdom — VAT
UK VAT is governed by the Value Added Tax Act 1994 and administered by HMRC. The standard rate is 20% (unchanged since January 4, 2011). A 5% reduced rate applies to domestic fuel and power, children’s car seats, and certain energy-saving home installations. Zero rate applies to most unprepared food, books, children’s clothing, and prescription medicines.
For UK freelancers reconciling VAT: the VAT fraction for the 20% standard rate is 1/6. Multiply the gross (VAT-inclusive) total by 1/6 to extract VAT — this fraction applies specifically at the 20% standard rate and would need to be recalculated if you’re working with the 5% reduced rate instead. Or divide by 1.20 to get the net. This calculator does both steps automatically. Some VAT rates change temporarily for specific goods or limited time windows (for example, hospitality-sector relief during 2020–2021); always confirm the rate that applied on the date of your receipt at HMRC’s VAT rates page rather than assuming the standard rate applies.
The results from this calculator are estimates based on the information you enter. For compliance decisions, verify with a qualified tax professional or official government source.
Reverse Sales Tax Calculator Examples: See the Math
Example 1: US Shopper Checking a Nashville Receipt
A shopper in Nashville paid $54.99 for a household item and wants to confirm how much of that was sales tax.
- Total price (tax included): $54.99
- Currency: USD
- Sales tax rate: 9.5% (Tennessee combined rate)
Calculation: $54.99 ÷ 1.095 = $50.22 pre-tax price. Tax charged: $54.99 − $50.22 = $4.77. Tax as % of total: 8.68%.
Result: Pre-tax price $50.22 | Tax charged $4.77 | Rate confirmed 9.5%
The retailer correctly charged $4.77 in sales tax — roughly 8.7 cents of every dollar paid went to tax, not 9.5 cents, because the rate applied to the base price, not the total.
Example 2: UK Freelancer Separating VAT from an Invoice
A consultant received a £1,200 payment for services that included 20% VAT and needs the net (ex-VAT) figure for her VAT return.
- Total price (tax included): £1,200
- Currency: GBP
- Sales tax rate: 20%
- Tax label: VAT
Calculation: £1,200 ÷ 1.20 = £1,000.00 net. VAT: £1,200 − £1,000 = £200.00. VAT as % of total: 16.67%.
Result: Pre-tax (net) price £1,000.00 | VAT charged £200.00
The £200 VAT is what she accounts for on her VAT return. Cross-check using the VAT fraction: £1,200 × (1/6) = £200 — same answer, since 1/6 is the VAT-extraction fraction specifically for the 20% standard rate. Export the CSV result directly to her accounting software to avoid manual re-entry.
Example 3: Verifying a Zero-Rate Purchase in Oregon
A buyer in Oregon paid $89.95 for electronics and wants to confirm that no sales tax was applied — Oregon levies no state sales tax.
- Total price (tax included): $89.95
- Currency: USD
- Sales tax rate: 0%
Calculation: At 0% rate, pre-tax price = $89.95. Tax charged: $0.00.
Result: Pre-tax price $89.95 | Tax charged $0.00 | “Zero rate: No tax was charged. Total paid equals the pre-tax price.”
If the seller had charged tax, entering the actual rate would expose the discrepancy instantly — the pre-tax price shown would be less than $89.95, and the difference would reveal the unauthorized charge.
FAQ
What is the formula for reverse sales tax?
Divide the total amount paid (including tax) by 1 plus the tax rate expressed as a decimal. For a 7.5% rate: total ÷ 1.075 = pre-tax price. The tax amount is the total minus the pre-tax price. This is how you back out sales tax from a total — the formula works identically for US sales tax, UK VAT, Canadian GST/HST, and Australian GST.
How do I reverse calculate VAT at 20% in the UK?
Divide the VAT-inclusive total by 1.20 to get the net (ex-VAT) amount. A £480 invoice at 20% VAT: £480 ÷ 1.20 = £400 net; VAT = £80. You can also use the VAT fraction: multiply the gross total by 1/6 — the result is the VAT amount, though this shortcut applies specifically at the 20% standard rate. [VERIFY-LAW] The standard UK VAT rate has been 20% since January 4, 2011.
Why is the tax as a percentage of my total lower than the tax rate?
Because the tax rate is applied to the pre-tax base, not to the final total. At a 10% rate on a $100 item, you pay $110. The $10 tax is 10% of $100 but only 9.09% of the $110 total. This is always mathematically correct — the “tax as % of total” figure in the breakdown will always be lower than the rate you entered, and that’s not an error.
Which US states have no sales tax?
[VERIFY-LAW] Five states levy no statewide sales tax: Oregon, Montana, New Hampshire, Delaware, and Alaska. Alaska is a partial exception — it has no state-level tax but allows local municipalities to collect their own, so parts of Alaska do have an effective rate above 0%. If you’re entering 0% in the calculator for one of these states, the result will confirm that the full amount you paid equals the pre-tax price with nothing remitted as tax.
Can I use this calculator for VAT, GST, or HST?
Yes. The reverse sales tax formula is the same for any tax that’s included in the price: total ÷ (1 + rate/100) = pre-tax amount. The calculator supports GBP, EUR, CAD, and AUD alongside USD, so you can remove tax from price correctly for UK VAT, Canadian GST/HST, and Australian GST. Use the Tax label field to label the result “VAT,” “GST,” or “HST” so the breakdown output matches your invoice or accounting record.
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DISCLAIMER:
This calculator performs a mathematical calculation only — it divides your entered total by 1 plus the rate you specify. It does not look up real tax rates for you. The US and UK rates referenced on this page were accurate at publication but change over time. Before using any rate for a filing, expense report, or VAT return, verify it with your state Department of Revenue, HMRC, or a tax professional. This page is not tax, legal, or financial advice. Last reviewed: July 2026.