What is Sales tax nexus?

Physical nexus vs. economic nexus

Physical nexus is the older, more intuitive standard: if you have property or people in a state, you have nexus there. For ecommerce that includes inventory you store in a state, which is exactly why Fulfillment by Amazon complicates things. When Amazon moves your FBA units into a fulfillment center in another state, many states take the position that you now have inventory there, and therefore physical nexus.

Economic nexus is purely about how much you sell into a state. After Wayfair, states can require out-of-state sellers to collect tax once their sales into that state cross a defined threshold, commonly framed as a dollar amount of sales, a transaction count, or sometimes either one. Those thresholds are set independently by each state and are periodically revised, so there is no single nationwide number. You have to check the current rule for every state you sell into rather than assume one figure applies everywhere.

A few other triggers catch sellers off guard. A remote employee or contractor working from a state can create nexus. So can attending a trade show, using a third-party prep center or warehouse, or in some states running affiliate links with in-state publishers. States also differ on the measurement window (a calendar year versus a rolling twelve months) and on whether marketplace sales count toward your threshold at all. Two states with identical dollar thresholds can reach opposite conclusions about the same seller.

Most of the large tax firms publish a state sales tax nexus chart, and those are a reasonable first map. Treat them as orientation rather than authority. Thresholds get revised, effective dates matter, and the chart you bookmarked last year may be describing a rule that changed in July. Confirm against the state's own department of revenue before you act on anything.

It's also worth knowing which states drop out of the question entirely. Delaware, Montana, New Hampshire, and Oregon impose no statewide sales tax, and Alaska has none at the state level though some localities levy their own. Those are the genuinely tax exempt states for this purpose, and no amount of sales volume into them creates a state sales tax obligation.

• •Physical nexus: an office, employees, contractors, or stored inventory in a state
• •FBA inventory: Amazon placing your units in a state can create physical nexus there
• •Economic nexus: sales into a state above that state's own threshold
• •Thresholds vary by state and change, so verify each state's current rule yourself
• •Measurement windows differ: some states look at a calendar year, others at rolling twelve months

How marketplace facilitator laws changed the picture

Before you panic-register in 45 states, understand marketplace facilitator tax. Most states now require the marketplace itself (Amazon, eBay, Etsy, Walmart) to collect and remit sales tax on the sales it facilitates, on the seller's behalf. So for the orders Amazon processes, Amazon is generally handling the collection and remittance for you, and you typically don't separately remit tax on those marketplace sales.

That doesn't make nexus irrelevant. You may still have a registration or filing obligation in states where you have nexus, even if the marketplace remits the tax, and some states want a return that reports those facilitated sales. Marketplace facilitator coverage only applies to sales through that marketplace: tax on sales through your own Shopify store or other direct channels is still your responsibility wherever you have nexus. Sellers who run multichannel almost always have a mixed obligation.

The practical effect is that your risk concentrates in your direct channel. A seller doing most of their volume on Amazon and a slice on Shopify can have a small dollar exposure and a large compliance one, because the Shopify orders are the ones nobody is collecting on. Sellers who launched a direct store as a side experiment are the ones most likely to be quietly out of compliance.

A worked example of a mixed obligation

Say you sell into a state where you've clearly crossed the economic threshold. Hypothetically, $180,000 of your sales into that state came through Amazon and $40,000 came through your own Shopify store. Amazon collected and remitted tax on its $180,000 as the marketplace facilitator, and you never saw that money as revenue. The $40,000 is yours to handle.

If the state counts marketplace sales toward the threshold (many do), you had nexus from the moment the combined figure crossed the line, not from when your direct sales alone would have. That's the trap: your Shopify store on its own would have looked harmless, but the Amazon volume dragged you over. From that point forward you needed to register, charge tax on those direct orders, and file returns, even though the marketplace was covering the bulk of the dollars.

Run the same numbers with the direct channel growing and the exposure compounds. Add a second direct channel, a wholesale account, or a pop-up event, and each one is another set of orders you're responsible for. The arithmetic is easy; the hard part is having sales-by-state data you actually trust.

How nexus shows up in your accounting

Sales tax you collect is never your revenue. It's money you're holding on behalf of a state. In your books it belongs in a sales tax liability account (a payable), increased when you collect and reduced when you remit. Booking collected tax as income is a common and expensive mistake that overstates revenue and understates what you owe.

The journal entries are simple once the accounts exist. A direct-channel sale of $100 with $8 of tax debits your clearing or receivable account $108, credits Revenue $100, and credits Sales Tax Payable $8. When you file and pay, you debit Sales Tax Payable and credit Cash. If your payable balance never goes to roughly zero after each filing, something upstream is misclassified.

If you key direct sales by hand, that split lives in the sales receipt. A QuickBooks Online sales receipt records a sale you've already been paid for, which describes most ecommerce orders, and the tax line on it has to map to your sales tax payable rather than to an income account. An invoice behaves the same way; the only difference is when the money arrives. Get the mapping right once and every future receipt inherits it.

Marketplace-facilitated tax adds a wrinkle: because Amazon collects and remits it, that tax flows through your settlement reports as amounts collected and withheld that you never touch. Your bookkeeping needs to net those out cleanly so they don't inflate your sales or your tax liability. This is exactly the kind of settlement detail BeanHawk is built to untangle, keeping facilitated tax separate from the tax you actually owe and remit yourself.

One more account worth setting up: a separate liability for tax you've collected in a state where you haven't registered yet. It happens more often than people admit, usually because a cart was configured to charge tax before the registration came through. That money is not yours and should never sit in revenue while you sort out the registration.

• •Collect on a direct sale: credit Sales Tax Payable, never Revenue
• •Remit to the state: debit Sales Tax Payable, credit Cash
• •Marketplace-facilitated tax: net out of settlements so it touches neither revenue nor your payable
• •Reconcile the payable to zero (or to the next filing) after every remittance

Common sales tax nexus mistakes

Treating collected tax as cash flow is the most damaging. That balance in your bank account belongs to states, and spending it on inventory in month one means finding it again in month three. Sellers who've been burned once keep the payable visible on a dashboard rather than buried in a monthly report.

Second: assuming marketplace facilitator laws cover everything. They cover the marketplace's own orders, not your Shopify checkout, not your wholesale invoices, not your Etsy-to-direct customers who reorder by email.

Third: registering everywhere out of caution. Registration creates a filing obligation, and a filing obligation you forget about generates penalties even on zero-dollar returns. Registering in a state you don't need to be in is a recurring cost, not a safety measure.

Fourth: not tracking sales by state at all. You can't monitor thresholds you can't measure, and reconstructing two years of state-level sales from raw order exports is a miserable weekend. Build it into your amazon bookkeeping routine before you need it.

Fifth: forgetting product taxability. Not everything is taxed the same way. Clothing, food, and supplements are treated differently across states, and a flat tax rate applied to a catalog with mixed taxability produces returns that are wrong in both directions. On Amazon this is driven by the product tax code you assign to each listing, and an Amazon tax code left on the default is how a seller ends up charging tax on exempt groceries in one state and skipping it on taxable ones in another. Sales tax on Amazon purchases is only as accurate as the codes underneath your catalog.

What to do if you discover past nexus

Finding out you've had nexus for a while is uncomfortable but survivable. The wrong move is to register normally and hope nobody looks backward, since registration often prompts a state to ask how long you've been selling there. The usual path is a voluntary disclosure agreement, where you approach the state proactively, typically get a limited look-back period, and often get penalties reduced or waived.

Quantify before you act. Pull sales by state and channel for every period in question, separate marketplace-facilitated orders from direct ones, and work out the actual uncollected liability on the direct sales. In a lot of cases the number is smaller than the panic suggests, especially for sellers whose direct channel is a minority of volume. A sales tax specialist earns their fee here, and they work faster when your books are already clean.

The reason to move rather than wait is that states do audit. A state sales tax audit is its own discipline, which is why accounting firms staff audit and tax work separately: the examiner's job is to test your exempt sales, the rates you applied, and your registration dates against your own records. Sellers who can produce sales by state and channel on request usually come through it fine. Sellers who can't spend months rebuilding history under a deadline someone else set.

A practical approach to staying compliant

The workable sequence for most sellers is: figure out where you have nexus, register where you're required to, let marketplaces remit what they're responsible for, and remit the rest yourself. Nexus reviews aren't one-and-done. As your sales grow and FBA spreads your inventory, your nexus footprint expands, so revisit it periodically.

Because the rules are genuinely state-specific and shifting, this is an area where professional guidance pays off. A sales tax specialist or one of the automated tax services can monitor your thresholds state by state, and a clean set of books makes that monitoring far cheaper. Treat the checklist below as what to confirm, not as fixed law.

Two housekeeping notes while you're in there. The marketplace tax form you receive, the 1099-K, reports gross payment volume and can include tax the marketplace collected, so it will never tie neatly to your sales tax filings; Amazon keeps it under Tax Central, in the Tax Document Library inside Seller Central, alongside your tax interview. And if you publish through KDP, that's a different relationship altogether: Amazon is the retailer of record for those books, so KDP tax forms concern your royalty income, not any sales tax you'd collect.

• •Map physical nexus, including every state where FBA stores your inventory
• •Track sales by state against each state's current economic-nexus threshold
• •Register in states where you've established nexus
• •Let marketplaces remit facilitated tax; remit direct-channel tax yourself
• •Re-check your nexus footprint as sales and FBA placement change

Tooling: what to expect from your accounting stack

Two different jobs get confused here. Sales tax compliance tools (Avalara, TaxJar and similar) calculate rates at checkout, monitor thresholds, and file returns. Ecommerce accounting tools record what happened and keep the liability accurate. You generally need both, and neither replaces the other.

Keep a third thing separate from both: rate calculators. A sales tax calculator tells you the rate at a given address, which is a checkout question, not a nexus question. The IRS sales tax deduction calculator is a different animal again, since it estimates the sales tax an individual can claim as an itemized deduction on a personal return and has nothing to do with tax you collect as a business. Sellers land on it constantly while searching for something else.

On the accounting side, the specific thing to test is settlement handling. Good amazon accounting software separates marketplace-facilitated tax from tax you collected yourself, so your sales tax payable reflects only what you actually owe. A2X and Link My Books both handle this mapping, and BeanHawk does it alongside inventory and COGS. If a tool dumps facilitated tax into revenue, or into your payable, you'll be unwinding it every month.

For direct channels, the same question applies to whatever connects your store to your ledger. Sellers running shopify accounting software or a shopify quickbooks integration should confirm that collected tax posts to a liability account, not to income, and that refunds reverse the tax correctly. Refund handling is where most connectors quietly get it wrong.

Frequently asked questions

What is sales tax nexus in plain terms?

It's a connection to a state strong enough that the state can require you to collect and remit its sales tax. That connection can be physical (an office, employees, or stored inventory) or economic (enough sales into the state). Without nexus you have no obligation there; with it, you generally must register, collect, and file.

Does selling through FBA create nexus in other states?

It can. When Amazon stores your FBA inventory in a fulfillment center in a given state, many states treat that as physical presence and therefore nexus. Because Amazon distributes inventory widely, FBA sellers often have nexus in more states than they expect, though marketplace facilitator laws mean Amazon usually remits the tax on those sales.

Is there one dollar amount that triggers economic nexus everywhere?

No. Economic-nexus thresholds are set by each state individually, usually framed as a sales-dollar amount, a transaction count, or either, and they get revised over time. There is no single nationwide number, so check the current threshold for each state you sell into rather than relying on one figure.

If Amazon collects the tax, do I still need to worry about nexus?

Often, yes. Marketplace facilitator laws make Amazon remit tax on sales it facilitates, but you may still owe registration or filing in states where you have nexus, and some states want a return reporting those sales. Tax on your direct channels, like your own Shopify store, remains entirely your responsibility wherever you have nexus.

How should collected sales tax appear in my books?

As a liability, not revenue. Sales tax you collect is money held for the state, so it increases a sales tax payable account when collected and decreases it when remitted. Booking it as income overstates revenue and hides what you owe. Marketplace-facilitated tax should be netted out of your settlements so it doesn't inflate either figure.

Do marketplace sales count toward my economic nexus threshold?

It depends on the state. Some exclude marketplace-facilitated sales from the threshold calculation, others include them, and that single difference decides whether a mostly-Amazon seller has an obligation on their small direct channel. Check the rule per state rather than applying one assumption across the board.

What happens if I've had nexus for a while and never registered?

Quantify the exposure first: sales by state and channel, with marketplace-facilitated orders separated out, since those were likely already remitted. Then look at a voluntary disclosure agreement, which typically limits the look-back period and reduces penalties for sellers who come forward before the state finds them. Talk to a sales tax specialist before registering, because registering first can invite backward-looking questions.

Does QuickBooks handle marketplace sales tax for Amazon sellers?

Not on its own. QuickBooks tracks a sales tax liability, but it has no idea which of your Amazon settlement lines represent facilitated tax that Amazon already remitted. That mapping comes from whatever connector sits between the channel and the ledger. If you're comparing amazon accounting software, ask specifically how facilitated tax is posted, and check that refunds reverse it correctly rather than leaving a stranded balance.

Related terms

Go deeper

• Amazon Seller Taxes: The Complete Guide to What You Actually Owe
• Ecommerce Sales Tax in Plain English: Nexus, Marketplaces, and You