Sales Tax Calculator
Add sales tax to a price, strip it back out of a total that already includes it, or work out the rate you were charged from a receipt. Handles quantities and discounts, shows a full receipt-style breakdown, and works with any tax rate anywhere — GST, VAT or state and local sales tax.
- Add tax to a price
- Reverse tax from a total
- Find the rate charged
- Quantity and discounts
Sales tax calculator
Discounts are applied before tax, which is how almost every till and invoicing system treats them.
Total including tax
—
Enter a price and a tax rate and the full breakdown appears here as you type.
- —Price before tax
- —Tax amount
- —Total with tax
- —Cost per item
Receipt breakdown
Extra detail
- Tax rate applied—
- Tax as a share of the total—
- Tax per item—
- Discount saved—
- Multiplier applied—
- Rounded to2 decimal places
Tills round each line differently, so a receipt can differ by a cent or two from any calculator. Treat this as the exact arithmetic rather than a prediction of the till.
Why this sales tax calculator is better
Adding a percentage is the easy half. The searches that go unanswered are the reverse ones — what was the price before tax, and what rate did they actually charge me?
True reverse calculation
Enter a tax-inclusive total and get the net price back. It divides by one plus the rate, which is the correct method — subtracting the percentage from the total is wrong and overstates the tax.
Work out the rate from a receipt
Have the before and after figures but not the rate? The third mode solves for it, which is useful for expense claims and for checking you were charged correctly.
Quantity and discount together
Most calculators handle one item at full price. This one multiplies the quantity and applies the discount before tax, the way a real invoice is built.
A receipt you can copy
Line items, discount, taxable amount, tax and total laid out like a till receipt, ready to paste into an invoice, an email or an expense report.
Any rate, any country
The maths is identical for US sales tax, Indian GST, UK and EU VAT or a provincial rate. Type the percentage you were charged and pick your currency.
Instant and private
Results update as you type, nothing is uploaded, and there is no sign-up or advert wall between you and the number.
How to calculate sales tax
Three formulas cover every version of this question.
Adding tax to a price
Multiply the price by the rate as a decimal to get the tax, then add it on. At 8.25 percent, one hundred becomes one hundred and eight point two five. The shortcut is to multiply by 1.0825 in one step.
Removing tax from a total
Divide the total by one plus the rate. A total of 108.25 at 8.25 percent divides by 1.0825 to give exactly 100. Subtracting 8.25 percent from the total instead would leave 99.32, which is the classic mistake.
Finding the rate
Divide the tax by the pre-tax price and multiply by one hundred. If 8.25 of tax sat on a price of 100, the rate charged was 8.25 percent.
Order matters with discounts
Apply the discount first, then charge tax on the reduced amount. Taxing the full price and deducting the discount afterwards leaves the buyer paying tax on money they never spent.
Who needs this
Anywhere a price and a percentage meet, and the difference has to be defensible.
- Shoppers. Work out what something will actually cost at the till in places where the shelf price excludes tax.
- Freelancers and small businesses. Split an inclusive total into net and tax for your books, or add the right amount to a quote.
- Expense claims. Many employers want the tax component listed separately, even when the receipt only shows a single total.
- Online sellers. Check that a marketplace has calculated tax correctly on a discounted multi-item order before you accept the payout.
- Travellers. Compare an inclusive price at home with an exclusive one abroad by putting both on the same basis.
- Anyone querying a bill. Copy the breakdown and send it back to the seller when the total does not look right.
Sales tax FAQs
The arithmetic, and the mistakes that cost real money.
How do I work out the price before tax?
Divide the tax-inclusive total by one plus the rate expressed as a decimal. At 20 percent that means dividing by 1.2, and at 8.25 percent by 1.0825. Do not subtract the percentage from the total — that gives a smaller, incorrect figure, because the percentage was charged on the net price, not on the total.
Why is subtracting the percentage from the total wrong?
Because a percentage is always taken of a base, and the base here is the pre-tax price. Twenty percent of 100 is 20, giving a total of 120. But twenty percent of 120 is 24, so subtracting it leaves 96 rather than 100. The error grows with the rate, which is why reverse calculations need division rather than subtraction.
What rate should I enter?
The combined rate that applies to your transaction. In the United States that is the state rate plus any county, city and special district rates, which vary within a single state and change from time to time, so use the figure on your receipt or your local tax authority's current table. Elsewhere it is usually a single national VAT or GST rate, sometimes with a reduced rate for particular goods.
Is sales tax applied before or after a discount?
Almost always after — the discount reduces the price, and tax is charged on what you actually pay. Manufacturer coupons reimbursed by a third party are treated differently in some jurisdictions, where tax may still be due on the full price. This calculator applies the discount first, which matches the standard retail case.
Why does my receipt differ by a cent?
Rounding. Some systems calculate and round tax on each line, others round only the invoice total, and rounding rules vary between half-up and banker's rounding. Those choices can move the final figure by a cent or two on a multi-item order. The result here is the exact arithmetic rounded once at the end.
Can I use this for VAT or GST?
Yes. The arithmetic is identical — only the name and the rate change. Enter 20 for UK VAT, 18 for a common Indian GST slab, or whichever rate applies. The reverse mode is particularly useful for VAT and GST, since prices in those systems are usually displayed inclusive of tax.
Does it know my local tax rate automatically?
No, deliberately. Combined local rates change frequently and differ street by street in some areas, so a stored table would eventually be wrong and you would have no way of knowing. Entering the rate from your receipt or your tax authority's current lookup keeps the answer accurate.
Is anything I enter saved?
No. Every calculation runs in your browser. Nothing is sent to a server, no account is needed and closing the tab clears the figures.
Get the number, both directions
Add tax, take it back out, or find the rate you were charged — with quantities, discounts and a receipt breakdown you can copy. Free, instant and with no sign-up.