The formula
How it works
Sales tax (or VAT) is a percentage added on top of a price at the till. Enter a pre-tax price to add tax, or a final price to work backwards and strip the tax out — handy for receipts that only show the total.
FAQ
How do I find the price before tax?
Switch to “Price with tax” and enter the total. The calculator divides it by 1 plus the rate to recover the pre-tax price.
Is sales tax the same as VAT?
The maths is identical — a percentage of the price. VAT is just the name used in the UK, EU and many other countries.
How do I calculate tax on a whole cart of items?
Add up the pre-tax prices first, then apply the rate once to the subtotal. That gives the same result as taxing each item separately, as long as every item shares the same rate.
Why does my receipt show a slightly different tax amount?
Many retailers round tax to the nearest cent per line item rather than on the total, so small rounding differences of a cent or two are normal.
Can I use this for a tax rate with decimals, like 7.25%?
Yes, the rate field accepts decimals, so rates like 7.25% or 8.875% work exactly the same as whole numbers.
Does this handle multiple stacked taxes, like state plus city tax?
Enter the combined rate as a single percentage — for example 6% state plus 1.5% city becomes 7.5% — since stacked flat-rate taxes simply add together.
How is removing tax different from applying a discount?
A discount is subtracted from the pre-discount price, while removing tax divides the total to find what the price was before tax was added — they use opposite arithmetic even though both involve a percentage.
About the sales tax calculator
This calculator adds sales tax to a price, or works backwards to remove it from a total. Sales tax is a percentage charged on top of the marked price of goods and services, collected by the seller and passed on to the government. Because rates differ by country, state and even city, a quick calculator saves you from guessing what a final bill will be — or what a receipt was before tax.
How to use it
First choose what you already know. If you have the price before tax, keep “Price before tax” selected, type the amount and the tax rate, and the calculator shows the tax and the final total. For example, a $100 item at a 7.5% rate has $7.50 of tax and costs $107.50. If instead you only have the final price, switch to “Price with tax”: entering $107.50 at 7.5% recovers the $100 net price and the $7.50 of tax. Change the currency if you are shopping abroad.
The formula
Adding tax uses , where is the price before tax and is the rate as a percentage; the total is . To go the other way and remove tax from a gross total , divide instead: the net price is , and the tax is whatever is left over. This reverse step is why you cannot simply subtract the percentage from the total — the percentage was taken of the smaller pre-tax figure, not the total.
Where it is used
Shoppers use it to check receipts and budget for the real cost of a purchase, while small businesses use it to set shelf prices and file tax returns. It is equally useful for freelancers adding VAT to an invoice, travellers comparing prices between regions, and students learning how percentages work on top of a base amount. The reverse mode is especially handy at tax time, when you need the net figure from a total that already includes tax.