Sales Tax Calculator
Add or remove sales tax and see the tax amount and total.
Add tax onto a net price, or strip embedded tax out of a gross price.
Total with tax
- Sales tax
- $8.25
- Pre-tax price
- $100.00
Each figure is rounded to the cent, and the pre-tax price plus tax sum to exactly the total.
How the sales tax calculator works
This tool does two jobs. In add mode it takes a pre-tax amount and adds the tax to find what you actually pay. In remove mode it takes a price that already includes tax and works backward to the pre-tax amount. Both use a single percentage rate, so the same calculator covers sales tax, VAT, and GST.
Adding tax is straightforward. The tax is the amount multiplied by the rate, and the total is the amount plus that tax:
tax = amount * rate / 100total = amount + tax
Removing tax is the part people get wrong. Because the total already contains the tax, you cannot simply take a percentage of it. Instead you divide by one plus the rate:
net = total / (1 + rate / 100)tax = total - net
The calculator rounds each result to the cent and derives the tax by subtraction, so the pre-tax price and the tax always add back to the total without drifting a cent.
Worked example
Say a meal is priced at 100 before tax and the local sales tax rate is 8.25 percent.
Adding tax:
tax = 100 * 8.25 / 100 = 8.25total = 100 + 8.25 = 108.25
So you pay 108.25, of which 8.25 is tax.
Now reverse it. Your receipt shows a total of 108.25 including 8.25 percent tax, and you want the pre-tax price:
net = 108.25 / 1.0825 = 100.00tax = 108.25 - 100.00 = 8.25
The pre-tax price is 100 and the embedded tax is 8.25, matching the forward calculation exactly. Notice that taking 8.25 percent of 108.25 would give 8.93, which is too high. That is the classic error remove mode avoids.
How to use it
- Choose add to go from a pre-tax price to the total, or remove to strip tax out of a tax-inclusive price.
- Enter the amount: the pre-tax price in add mode, or the price including tax in remove mode.
- Enter the rate as a percent, for example 8.25 for 8.25 percent, not 0.0825.
- Pick your currency from the selector. The math is the same in every currency.
- Read off the tax, the pre-tax price, and the total with tax.
Limitations
This is an estimate for a single combined rate. It does not handle tax-exempt items, partial exemptions, tiered or bracketed rates, or jurisdictions where several taxes apply to different parts of a bill. If your purchase mixes taxed and untaxed items, calculate each part separately. Always treat your receipt or invoice as the authority for the exact figures.
Frequently asked questions
What is the difference between adding and removing tax?
Adding tax starts from a pre-tax price and works out the tax and the final amount you pay, so a 100 item at 8.25 percent becomes 108.25. Removing tax does the opposite: it starts from a price that already includes tax and recovers the pre-tax amount, so 108.25 at 8.25 percent reveals a pre-tax price of 100. Use add mode when a sticker shows the price before tax, and remove mode when a receipt total already includes it and you want the net figure.
How do you remove sales tax from a total?
You divide the tax-inclusive total by one plus the rate as a decimal. At 8.25 percent that is dividing by 1.0825. So 108.25 divided by 1.0825 gives a pre-tax price of 100, and the tax is the remaining 8.25. A common mistake is to take 8.25 percent of the gross total instead, which overstates the tax because the gross already has tax baked into it.
Why might the tax be a cent off what I expected?
Tax is rounded to the nearest cent, and so is the total. When the raw tax lands on a half cent it rounds up, which can move a result by a cent versus a hand calculation that keeps extra decimals. The calculator rounds at the end and derives the pieces so that the pre-tax amount plus the tax always add back to the total exactly.
Does this handle any country or currency?
Yes. The math is the same everywhere: a single percentage rate applied to an amount. Pick your currency from the selector and enter the combined rate that applies to your purchase. For places with several stacked taxes, add them into one combined percentage first.
Is this the same as VAT or GST?
The arithmetic is identical. VAT and GST are value-added taxes charged as a percentage of price, so adding or removing them uses the exact same formulas. Enter your VAT or GST rate in the rate field and the results read the same way.