Sales tax (US), VAT (Europe, UK), GST (Canada, Australia, India, NZ, Singapore) and consumption tax (Japan) are all transaction taxes — but they differ in who collects, when it applies, and whether the displayed price already includes it. This calculator handles every variant with the same controls.

In the US, prices are usually shown ex-tax and the rate stacks state + county + city. Use Add Tax mode and the 'Additional Local/County %' field to model combined rates like 8.875% in NYC. In Europe and most VAT/GST regions, shelf prices are inclusive — use Remove Tax to extract the net component for bookkeeping.

Reverse Solve is useful when you have a target final price (e.g. 'I want this to ring up at exactly $100') and need to know the pre-tax price to enter. Margin/Markup mode goes the other way: given your cost and target margin, it returns the sell price both ex- and inc-tax so you can list a retail price that still hits your profit goal.

The Cart mode mirrors an invoice — every line can have its own rate or be marked exempt (e.g. groceries in many US states, books in some EU countries). Rounding follows real-world POS behavior: most jurisdictions round per-invoice to the nearest cent, but a few (Switzerland, parts of Canada for cash) round to 0.05.