Add tax to a pre-tax price, or strip tax out of a tax-inclusive total. Works for any rate worldwide.
Use Add when you have a net price and want to know the final amount to charge. Use Remove when you have a gross (tax-inclusive) total and need to split it into net price and tax amount.
Both add a percentage on top of a base price, but they're collected differently. Sales tax, used in the US, is generally applied once, at the final sale to the consumer. VAT (value-added tax), used across the EU, UK, and many other countries, is collected incrementally at each stage of production and distribution — though in practice, the end consumer still ends up paying the full cumulative amount, similar in effect to a single-stage sales tax from their perspective.
Rates also aren't always uniform within a country. In the US, sales tax is typically set at the state level and often layered with additional city or county tax, so the effective rate on an identical purchase can vary meaningfully by location.
Sales tax, common in the US, is typically charged once at the final point of sale. VAT, common in the EU, UK, and elsewhere, is collected incrementally at each production stage, though the end consumer bears the full amount either way.
Receipts, invoices, and some advertised prices show a tax-inclusive total. If you need the pre-tax price — for bookkeeping, expense reports, or comparing across regions — you have to work backward from the total.
Yes, in many countries. In the US, sales tax is set at the state and often city or county level, so the rate for the same purchase can differ significantly depending on exactly where it takes place.