When Selling Online Gets Complicated
You set up your online store, start making sales, and then someone asks: “Are you collecting sales tax?” Suddenly, a question that seemed simple turns into a rabbit hole of state laws, thresholds, and compliance rules. Sales tax for e-commerce is one of those topics that trips up new sellers constantly — and even experienced ones sometimes get it wrong.
The good news is that the core concepts aren’t as intimidating as they look once you break them down. Here’s what you actually need to understand.
How Sales Tax Works in the U.S.
Unlike countries with a single national sales tax, the United States leaves it up to individual states to set their own rules. That means rates, exemptions, and filing requirements can vary dramatically depending on where your buyer lives. Some states have no sales tax at all — Oregon, Montana, New Hampshire, Delaware, and Alaska among them. Others, like California and Tennessee, have rates that climb above 9% when you factor in local taxes.
Sales tax is generally a destination-based tax. This means the rate that applies is the one in effect where the buyer receives the product, not where the seller is located. If you’re in Texas and you sell a pair of shoes to someone in New York, New York’s rules apply to that transaction.
Nexus: The Concept That Changes Everything
Before you’re required to collect sales tax in any state, you need to have what’s called a nexus there. Think of nexus as a significant connection to a state — and it comes in two main forms.
Physical Nexus
This is the traditional kind. If you have an office, warehouse, employee, or inventory stored in a state, you have physical nexus there. A seller based in Illinois with a fulfillment warehouse in Ohio, for example, has nexus in both states and must collect sales tax from buyers in each.
Economic Nexus
This one changed the game. After the 2018 Supreme Court ruling in South Dakota v. Wayfair, states gained the authority to require out-of-state sellers to collect sales tax based purely on sales volume — no physical presence needed. Most states now enforce an economic nexus threshold of $100,000 in sales or 200 transactions per year within their borders. Cross that line, and you’re on the hook for tax collection.
Marketplace Facilitators: A Shift in Responsibility
If you sell through platforms like Amazon, Etsy, or eBay, there’s some relief. Most states have passed marketplace facilitator laws, which require the platform itself to collect and remit sales tax on behalf of sellers. This doesn’t mean you’re completely off the hook — you still need to track your own sales and understand where you might have independent obligations — but it does simplify things considerably for sellers who rely heavily on third-party marketplaces.
Product Taxability: Not Everything Is Taxable
Here’s something that catches a lot of sellers off guard: not every product is taxable in every state. Groceries are exempt in many states. Clothing is exempt in New York for items under $110. Prescription medications are widely exempt across the country. Digital products like e-books or software subscriptions? That depends entirely on the state.
Before assuming a tax rate applies to your product, it’s worth checking the specific rules for each state where you have nexus. A product that’s fully taxable in one state might be completely exempt in another.
Getting Compliant Without Losing Your Mind
For small sellers just getting started, the process typically looks like this:
- Identify the states where you have nexus (physical or economic).
- Register for a sales tax permit in each of those states — you can’t legally collect tax without one.
- Set up your e-commerce platform to apply the correct tax rates automatically.
- File and remit collected taxes on the schedule each state requires (monthly, quarterly, or annually).
Tools like TaxJar, Avalara, and even built-in features on Shopify or WooCommerce can automate a large portion of this process. They won’t replace professional advice in complex situations, but they handle the heavy lifting for most straightforward businesses.
Staying Ahead of the Rules
Sales tax law isn’t static. States update thresholds, add new product categories to taxable lists, and occasionally change filing deadlines. The sellers who avoid trouble are the ones who treat compliance as an ongoing process rather than a one-time setup. Reviewing your nexus status once or twice a year — especially as your sales grow — goes a long way toward keeping you out of trouble and your business running smoothly.
