Internet Sales Tax Explained: What It Is and When It Applies
Internet sales tax is now the rule. Learn when nexus triggers collection, how marketplace laws work, and avoid costly penalties in every state.
Written by: Chad Evans
Date of publication: 19.02.2026
Table of Contents
Today, the reality for American shoppers is that, for the vast majority, paying internet sales tax is no longer the exception; it’s the rule. Following the Wayfair decision, states moved quickly to require remote sellers to collect sales tax, and with more than 80% of Americans now shopping online, compliance has become the norm.
If you want help building a repeatable sales tax process, our accounting & compliance services include sales tax support.
But what exactly is this tax, and when does it apply? How do you avoid the kind of mistakes that lead to back penalties and legal headaches? Explore this quick guide to learn more.
Key Takeaways
- Internet sales tax is now the norm, not an exception, for most online purchases in the U.S.
- There is no separate “internet-only” tax - states are applying their existing sales tax rules to online sales.
- Sales tax rules aren’t federal; they vary by state, creating a patchwork of rates, exemptions, and filing requirements.
- Your obligation to collect tax is triggered by nexus, which can be physical (presence, employees, inventory, FBA) or economic (sales thresholds).
- Many states use economic nexus thresholds around $100,000 in annual sales, meaning even small brands can be required to collect.
- Marketplace facilitator laws often make platforms collect and remit tax, but marketplace sales may still count toward your nexus thresholds.
- The biggest compliance risks are failing to track nexus, charging the wrong local rate, and missing filing deadlines - each can lead to penalties and back taxes.
What Is Internet Sales Tax?
Simply put, sales tax on internet sales is the tax applied to items bought online. For years, the “physical presence” rule acted as a shield for online sellers, but that changed. Now, states want their cut of the digital pie to ensure local brick-and-mortar shops aren’t being undercut by tax-free online competition. This is especially important for omnichannel brands – here’s how we support retailers: retail accounting services.
Is Internet Sales Tax a Separate Tax?
There’s no special “internet only” tax code. When people talk about it, they’re really talking about extending existing state sales taxes into the digital world. It’s the same tax you pay at a local convenience store, just collected through a virtual checkout.
How Internet Sales Tax Works
Understanding how the sales tax on internet purchases works can be daunting because there is no single federal rule. Instead, you’re dealing with a patchwork of state laws that determine how much to charge and where that money goes.
Sales Tax on Internet Sales vs In-Store Sales
Feature | In-Store Sales | Internet Sales |
Tax basis | Based on the store’s physical location | Typically based on the buyer’s location (destination-based) |
Complexity | Straightforward calculation at checkout | Requires tracking multiple jurisdictions and varying local rates |
Nexus consideration | Always tied to the store’s state and local area | Determined by physical or economic nexus; may involve multiple states |
Exemptions | State and local exemptions apply | Same exemptions apply, but must verify by customer location |
Collection responsibility | Store collects and remits tax | Seller collects if responsible; marketplaces may handle collection on behalf of third parties |
Filing requirements | Single state or local return | May require multiple filings across states and local jurisdictions |
If you operate across states, nexus rules can spill into other filing requirements too – see our multi-state filing guide.
Sales Tax on Internet Purchases
Sometimes, a seller doesn’t meet the legal threshold to collect tax. In that case, the buyer is technically responsible for paying the “use tax.” While most shoppers don’t realize it, they are legally required to report sales tax on internet purchases to their own state if the retailer didn’t charge it at the time of sale.
Ready to Simplify Your Internet Sales Tax?
Who Has to Collect Internet Sales Tax?
The obligation to collect and remit internet sales tax generally falls on three main types of entities, depending on their business model and size:
1. Online Retailers
These sellers are directly responsible for monitoring their sales in every state. If they exceed a state’s economic nexus threshold, they are required to register, collect, and file taxes in that state. Solid recordkeeping makes that doable – especially for sales tax across multiple jurisdictions: understanding ecommerce bookkeeping.
2. Marketplaces
When you make a sale on an online marketplace like Amazon, the platform typically calculates, collects, and remits the tax to the state. However, this doesn’t absolve you of all responsibility. You still need to be aware of these sales, as they often count toward the economic nexus threshold for your own direct sales through other channels.
3. Digital Platforms and Facilitators
Most states have enacted “marketplace facilitator” laws. The law defines a marketplace facilitator as a person or entity that contracts with sellers to facilitate sales through a physical or electronic marketplace and engages in activities such as payment processing and fulfillment. They are legally treated as the seller for tax collection purposes on the transactions they facilitate.
When Does Internet Sales Tax Apply?
The trigger for being required to collect the internet sales tax is “nexus,” a legal term meaning a sufficient connection to a state. There are two primary ways an online seller creates this connection today: physical and economic.
Physical Nexus
If your business has a physical presence in a state, you have nexus and must collect tax. This includes obvious things like having a storefront, an office, or a warehouse. But it can also include less obvious connections, such as an employee working remotely from that state, a contractor, or even inventory stored in a third-party warehouse, such as those used by Amazon’s Fulfillment by Amazon (FBA) program.
Economic Nexus
The post-Wayfair world is defined by economic nexus. This means that, even without a physical presence, an out-of-state seller can be required to collect tax if their economic activity within a state exceeds a certain threshold. Many states use a $100,000 sales threshold, but there are major exceptions (e.g., California and Texas at $500,000; Alabama and Mississippi at $250,000; New York requires $500,000 plus 100 transactions).
Marketplace Facilitator Rules
If you sell exclusively on a marketplace like eBay and have no other sales, you likely don’t need to register for tax yourself because the facilitator law requires the platform to handle it. However, if you also have a standalone website, sales from that website, combined with your marketplace sales, could push you over a state’s economic nexus threshold, triggering a requirement to register and collect tax on your direct sales.
Internet Sales and Sales Tax by State
Perhaps the most challenging aspect of internet sales and sales tax is that the United States lacks a unified system. There are 45 states with a statewide sales tax, plus the District of Columbia, and each one is its own sovereign taxing authority with its own rules.
That state-by-state complexity shows up elsewhere too – here’s a primer on state income tax apportionment and why nexus matters.
In a “destination-based” state, you must charge your customer the tax rate in effect where the customer is receiving the goods. The vast majority of states are destination-based. In an “origin-based” state, you charge the tax rate based on where your business is located, even if the customer lives across the state. To complicate matters further, a state like California operates a hybrid system, using origin rules for some taxes and destination rules for others.
There are five states that do not impose a statewide sales tax: Alaska (it can have local sales taxes), Delaware, Montana, New Hampshire, and Oregon. If your business is located in one of these states, it doesn’t automatically exempt you from collecting tax on sales to customers in other states. Once you cross a threshold in, say, Georgia, you must collect and remit tax to Georgia, even if your home state doesn’t have a sales tax.
If you sell into multiple states, you may be dealing with thousands of local tax jurisdictions.
(The US has 12,000+ sales/use tax jurisdictions.)
What Online Sellers Must Do to Stay Compliant
Staying compliant is a process, not a one-time event. It requires a systematic approach to managing your tax obligations. For starters, it can help if you:
- Register for sales tax permits after determining you have nexus in a state
- Calculate correct tax rates by applying the right rate for every transaction
- File returns and remit payments regularly, whether monthly, quarterly, or yearly
If you want a practical starting point for staying organized, use our tax preparation checklist for small business.
Common Internet Sales Tax Mistakes
1. Failing to track the nexus
This is the most common and dangerous mistake. A business grows, starts hitting $80,000 or $90,000 in sales in a state, and the owner is unaware of the economic nexus laws. By the time they hit $100,000, they have a past-due obligation. They should have been registered and collecting months ago, potentially leading to a liability for uncollected taxes coming out of their own pocket.
2. Charging incorrect tax rates
Using a “one rate fits all” approach is a surefire way to get into trouble. Charging a flat 6% on all orders when customers are located in areas with a 7.5% or 8% total rate (combining state and local taxes) leaves a shortfall that you may be liable for. Relying on outdated rate tables is also a common issue, as rates change frequently.
3. Missing filing deadlines
With multiple states, each with its own due dates and filing frequencies, it’s easy to lose track. A quarterly filer in one state might have a different quarter-end than a monthly filer in another. Missing these dates triggers automatic penalties and interest, which are pure losses for your business.
Conclusion
Navigating internet sales tax is undeniably complex, a patchwork of state laws and thresholds that have fundamentally changed the e-commerce playing field. It’s no longer a tax that applies only to the “big guys.” From the solo entrepreneur with a warehouse of inventory in another state to the growing brand hitting six figures in sales, understanding when and where you have an obligation is a crucial part of running a modern online business.
FAQ
- Q1: Is internet sales tax a separate tax?
A: No - it's your usual state sales tax applied to online purchases. The rules changed after Wayfair, so states can require remote sellers to collect it.
- Q2: What is “nexus” and why does it matter?
A: Nexus is your connection to a state. If you have it, you may have to register, collect, and remit sales tax there - even if you don’t live or have a store there.
- Q3: What creates physical nexus for online sellers?
A: A warehouse, office, storefront, employees, contractors, or inventory stored in-state (including FBA warehouses) can trigger physical nexus.
- Q4: What is economic nexus in plain English?
A: It’s when your sales activity in a state is “big enough” to require tax collection, even with no physical presence - often around $100k in annual sales.
- Q5: If I sell on Amazon/eBay, do I still need to collect tax?
A: Usually the marketplace collects and remits. But your marketplace sales can still count toward nexus thresholds, especially if you also sell on your own site.
- Q6: What’s the difference between destination-based and origin-based tax?
A: Destination-based uses the buyer’s delivery location rate (most states). Origin-based uses your business location rate. Some states use hybrids, which adds complexity.
- Q7: What is use tax, and when does it apply?
A: If a seller doesn’t charge tax, the buyer may owe “use tax” to their state. It’s legal responsibility many shoppers overlook.
- Q8: What’s the fastest way to avoid penalties?
A: Track sales by state, watch for threshold creep, register as soon as nexus is triggered, use accurate rate tools, and build a calendar for filing deadlines.
Related Tips & Topics
