Adobe expects Americans to spend a record $275.1 billion online between November 1 and December 31 this year, including $12.9 billion on Black Friday alone. Almost every one of those orders will carry a line near the bottom of the cart that few people read closely: sales tax. Online sales tax used to be the internet’s quiet discount. It isn’t anymore, and the part that still varies from order to order isn’t the part most people think.
Since 2018, the rate on your online order has been set by where the package lands, not where the store sits. The store is just the collector. What’s left to vary is how your state treats the shipping charge, and in some states, an item listed with “free shipping” can carry more tax than the identical item with shipping billed separately.
Online sales tax follows your address, not the seller’s
Sales tax in the U.S. is entirely a state and local creation. There’s no federal sales tax, so every state writes its own rules, and thousands of cities, counties, and special districts stack their own rates on top. The Tax Foundation’s midyear 2026 tables put the population-weighted national average combined rate at 7.53%. The top five average combined rates belong to Louisiana (10.13%), Tennessee (9.61%), Washington (9.57%), Arkansas (9.48%), and Alabama (9.46%). Five states have no statewide sales tax at all: Alaska, Delaware, Montana, New Hampshire, and Oregon, though Alaska lets localities levy their own, averaging 1.82%.
For online orders, nearly every state uses what’s called destination sourcing. The tax due is calculated from the address where you take delivery. That’s why your total changes when you switch the shipping address from your apartment to your parents’ house in another state, even though nothing else about the order moved.
Since Wayfair, the store is only the tax collector
For decades, this system had a giant hole in it. A 1992 Supreme Court decision, Quill v. North Dakota, said a state could only force a seller to collect its sales tax if the seller had a physical presence there, such as a store, a warehouse, or employees. An online retailer with no footprint in your state didn’t have to charge you anything.
Technically you still owed the tax. It’s called use tax, and it applies when you buy something taxable without paying sales tax on it. In practice, almost nobody paid it. The Government Accountability Office estimated in a November 2017 report that state and local governments could have collected about $8 billion to $13 billion more in 2017 if they had been able to require all remote sellers to collect.
That changed with South Dakota v. Wayfair in June 2018. South Dakota had passed a law requiring out-of-state sellers to collect if they made more than $100,000 in sales or 200 separate transactions into the state in a year. The Court upheld it 5 to 4 and overruled Quill. The physical presence test was gone, replaced by what tax people call economic nexus: sell enough into a state, and you collect its tax.
States moved fast. Within a few years, every state with a sales tax had adopted economic nexus rules, with Missouri the last, taking effect January 1, 2023. Each also passed a marketplace facilitator law, which makes platforms like Amazon, Etsy, and Walmart.com collect tax on behalf of the third-party sellers using them. That second piece matters more than it sounds. A tiny seller on a big marketplace might fall well below a state’s threshold, but the marketplace doesn’t, so the tax gets charged anyway.
Use tax never went away, it just got smaller
The rules didn’t erase use tax. They just shrank the places it applies. If you buy from a small independent site that sells below your state’s threshold and isn’t on a marketplace, it may not charge you tax, and you’re still technically on the hook for paying it yourself. Many state income tax returns include a line for exactly this. Few people fill it in, and enforcement on individuals is rare, but it’s worth knowing that “the website didn’t charge me tax” and “I don’t owe tax” are not the same statement.
Sales tax on shipping is where states still disagree
Shipping is where online sales tax gets inconsistent, because each state decides whether delivery charges are part of the taxable price.
Texas takes the broad view. The Texas Comptroller states that for items shipped into the state, “the sales price includes all shipping and handling charges.” Tax applies to the whole thing.
California takes a narrower view. According to the California Department of Tax and Fee Administration, delivery charges on a taxable sale are not taxable when the item ships directly to you by common carrier, contract carrier, or the U.S. Mail, the charge is listed separately on the invoice, and it’s no more than the seller’s actual delivery cost. Anything above actual cost is taxable, as is a separately stated handling fee. And if delivery is folded into the item’s price, the full price is taxable.
That last rule is where “free shipping” can quietly cost you. Picture the same $800 laptop sold by two retailers. Retailer A charges $800 plus $40 for UPS shipping, listed separately. Retailer B charges $840 with free shipping. You pay $840 before tax either way.
Shipped to a California address at the state’s 9.03% average combined rate, Retailer A’s order is taxed only on the $800: $800 × 0.0903 = $72.24. Retailer B’s is taxed on the full $840: $840 × 0.0903 = $75.85. Same laptop, same total price, $3.61 more in tax because of how the receipt is worded.
Ship both to a Texas address at the 8.20% average and the difference vanishes. Texas taxes shipping either way, so both orders owe $840 × 0.082 = $68.88. Send them to Oregon and both owe $0.
Three dollars and change won’t wreck anyone’s holiday budget. What it does is explain a thing that looks like an error and isn’t. Two carts with identical totals can produce different tax lines, and both retailers calculated correctly. The difference was decided in Sacramento, not at checkout.
Your tax line changes because your address changed, not the store
Knowing that the store is only the collector also clears up a few checkout mysteries. The tax on your order can change when you edit the shipping address, because the rate is pulled from that address, sometimes down to the specific local district. Items bought from a third-party seller on a big marketplace get taxed even if the seller is tiny, because the marketplace is the one collecting. And returns work in reverse: when a retailer refunds a taxable purchase, the sales tax you paid on it is normally refunded too, so check that the tax line comes back with the item price.
So online sales tax is your local tax, charged at your address’s rate and collected by whoever sold you the thing. Switching to a different website won’t shrink it. With U.S. e-commerce sales reaching $340.2 billion in the second quarter of 2026, about 17.1% of all retail according to Census Bureau data, the old gap that let online orders skip the tax is effectively closed. The variation that’s left lives in the fine print about shipping, and that fine print is set by your state, one rule at a time.
If you’re curious how retailers price the deals that land in those carts, our explainer on how Black Friday doorbusters work covers the other side of the receipt, and how retailers track returns explains what happens after you send something back.
