Sales Tax Calculator

Sales tax, VAT and GST, explained for real purchases

Sales tax in the United States is a consumption tax added at the point of sale, on top of the listed price. It is set by states and stacked with county, city and special-district rates, which is why the rate at a register in one town differs from the next. The headline figure most people care about is the combined rate, the statewide base plus the average local add-on, which this tool uses by default for every state.

Value-added tax (VAT) in Europe and goods-and-services tax (GST) in Canada, Australia, India and elsewhere achieve the same goal differently. VAT and GST are usually already included in the shelf price you see, and they are collected in stages along the supply chain rather than only at the final sale. That is why a £120 price tag in the UK already contains £20 of VAT: to find the net you divide by 1.20, you do not subtract 20%.

The math is symmetric. To add tax, multiply the price by one plus the rate; to extract it, divide the inclusive total by one plus the rate. The gap between those two operations is where money leaks: on a $108.50 total at 8.5%, subtracting 8.5% gives $99.27, but the real pre-tax price is $100.00. Over hundreds of invoices that 73-cent drift per item becomes a reconciliation headache, which is why bookkeepers reach for Extract mode.

Five states, remembered as NOMAD (New Hampshire, Oregon, Montana, Alaska and Delaware), levy no statewide sales tax, though Alaska permits local taxes that average about 1.8%. At the other end, Louisiana and Tennessee sit near 9.5% combined. Many states also exempt unprepared groceries and prescription drugs, run back-to-school tax holidays, and tax prepared food and digital goods under their own rules, so the exempt-portion field lets you mark part of a cart as untaxed.

Since the 2018 Wayfair decision, physical presence is no longer required for a state to tax a sale. Economic nexus, commonly $100,000 in sales or 200 transactions into a state, now obliges most online sellers to collect destination-based tax at the buyer's address. That is the rule this calculator assumes, which is why picking the buyer's state, not the seller's, gives the figure a modern checkout will charge.

For a buyer the practical takeaway is simple: budget the total, not the sticker. For a seller, collect the right rate, record the net and the tax separately, and remit on schedule. For both, the rule of thumb is that the rate matters most when you are deciding where to buy a big-ticket item, while the amount dominates a single everyday purchase, exactly what the sensitivity panel above shows.