Why Sales Tax Rates Vary So Much

Unlike a national VAT used in many countries, sales tax in places like the United States is typically set at the state level, and often stacked with additional county or city rates — meaning two people in the same state, but different cities, can legitimately pay different combined tax rates on an identical purchase. Some categories of goods (groceries, prescription medication, clothing in some states) are also commonly tax-exempt or taxed at a reduced rate, which is why the "obvious" calculation doesn't always match a real receipt. Always use your local rate rather than a general assumption — rates vary by country, and within countries like the U.S., by state, county, and sometimes city.

How Sales Tax Is Calculated

Sales tax is added on top of a listed price, at a rate set by your state, county, city, or country — not by the business selling the item.

Working Backwards: Finding the Tax Rate from a Receipt

Sometimes you have the pre-tax price and the total, and want to know what tax rate was actually applied:

One more thing worth knowing: whether you should tip before or after tax is added is a common point of confusion at restaurants specifically — see the dedicated guide below for a full breakdown with worked examples.