Sales Tax Calculator

Sales tax, called VAT or GST in many countries, is a percentage added to the price of most goods and services at the point of sale. In some places the price you see excludes it and it appears at the till; in others the displayed price already includes it. Knowing which applies, and how to reverse one into the other, saves confusion and, occasionally, money.

Adding tax is straightforward: multiply the net price by the rate and add it on. A hundred-dollar item at eight and a quarter per cent becomes a hundred and eight twenty-five. Reversing it is the trickier direction, and the mistake is to subtract the same percentage. Taking eight and a quarter per cent off a tax-inclusive total does not return the original net price, because the tax was calculated on the lower base. To reverse correctly you divide by one plus the rate, not multiply by one minus the rate.

That asymmetry is why businesses and buyers sometimes disagree by a few cents, and why a correct reverse calculation matters for invoices, expense reports and refunds. If you paid a total and need to know the tax alone, extracting it properly keeps your books straight.

Rates are rarely a single number. Federal, state, county and city layers can stack, and different categories of goods are often taxed differently — food and medicine may be exempt or charged at a lower rate, while luxury or sin goods attract more. Cross-border online shopping adds another wrinkle, since the rate applied depends on where the buyer is, and rules have tightened in many jurisdictions.

Use this calculator to add or extract sales tax for a given rate and amount, and to check a receipt or invoice. It uses the rate you enter; for exact figures on a real transaction, apply your local rules and the rate that legally applies.

This calculator returns estimates for general information only. It is not financial, investment, tax or legal advice, and it cannot replace guidance from a qualified professional who knows your circumstances. Figures such as loan payments, investment growth and retirement projections are simplified models based on the inputs and assumptions you provide, not guarantees of future results.