If you already run an operating store — real orders, real ad spend — the question is not "what is nexus" in the abstract. It is "which states am I on the hook for right now, and how much of my profit is leaking because I got it wrong?" This guide answers that for an operator, with numbers.
This is general information, not tax advice. Rules change and vary by situation — consult a licensed CPA or tax professional before acting.
What sales tax nexus actually means
Nexus is the trigger. Cross it in a state and you take on four separate jobs: register, collect at checkout, file returns, and remit the money. Most articles blur these together — they are four distinct obligations, and Shopify only helps with one of them (collecting).
There is no federal sales tax in the US. Every rule is set state by state, which is why a store shipping nationwide can owe in dozens of jurisdictions with dozens of different thresholds, rates, and due dates.
Two things create nexus: physical presence and economic activity.
Physical nexus
Physical nexus is the old rule: a tangible tie to a state. An office, an employee, a contractor, a warehouse, or inventory stored there all count. Your home state almost always gives you physical nexus on day one.
For print-on-demand operators there is a hidden version of this. If your supplier prints and warehouses goods that are legally yours in a given state, that inventory can create physical nexus for you there. Most POD sellers using Printify, Printful, or Gelato don't hold title to blank inventory, so this usually doesn't bite — but if you hold stock in a 3PL, check it.
Economic nexus
Economic nexus is the one that catches growing stores off guard. It was created by the 2018 Supreme Court decision South Dakota v. Wayfair, which let states tax remote sellers with no physical presence at all, based purely on sales volume, as Stripe explains.
Sell enough into a state and you owe there — even if you have never set foot in it. That is the whole mechanic. The only variable is where each state draws its line.
Economic nexus thresholds by state
There is no single national number, and articles that quote "$100,000 or 200 transactions" as if it were universal are setting you up to under-collect or over-collect.
The most common threshold is $100,000 in sales OR 200 transactions into that state over twelve months, according to Avalara's state-by-state economic nexus guide. But the exceptions matter:
- Higher dollar bars. Texas uses $500,000 with no transaction count, and California uses $500,000, per Avalara's guide. A store doing $200,000 into Texas owes nothing there yet; the same store owes in a $100,000 state.
- Dropped transaction tests. Several states have scrapped the 200-transaction trigger in favor of a dollars-only test. Illinois removed its 200-transaction threshold effective January 1, 2026, leaving a $100,000 gross-receipts test, as Avalara notes.
Why the transaction count is the dangerous one for POD: it's tied to order count, not dollars. A low-AOV store can blow past 200 transactions in a state long before it hits $100,000 in sales there.
Say you sell a $31 tee and about a fifth of your 340 monthly orders ship to one populous state. That's roughly 68 orders a month into that state, or 816 a year — four times the 200-transaction line — on only about $25,000 of sales. In a state that still counts transactions, you crossed nexus at order 201, not at dollar 100,001.
That single distinction is why you cannot manage nexus by watching total revenue. You have to watch it per state, on both axes.
What Shopify does — and the three things it won't
This is where operators lose money quietly. On a standard storefront, Shopify calculates the correct rate at checkout and collects the tax from the buyer — but only after you tell it where you have nexus. It does not register you, it does not file your returns, and it does not remit the collected tax to the state. Those three stay entirely on you.
Money Shopify collects labeled "sales tax" is not revenue. It is money you hold on the state's behalf and must send in. Booking it as income is one of the most common ways small stores overstate profit — walk through how to set collection up correctly in our guide to configuring Shopify sales tax.
One exception worth knowing: the Shop app is treated as a marketplace facilitator for US sales tax as of January 1, 2025, so Shopify calculates, collects, remits, and files for orders placed through the Shop app, per Craftybase's breakdown. Your regular storefront orders get none of that treatment — there, you are the seller of record.
That last term matters. Every US state with a sales tax now has a marketplace facilitator law, which is why Amazon and Etsy handle tax for you, Avalara reports. Your own Shopify store is not a marketplace. The obligation is yours.
The profit angle nobody covers
Here is the part the ranking guides skip: nexus is a margin problem, not just a compliance problem.
Say your store runs 340 orders a month at a $31 AOV — about $10,540 in monthly sales — with $2,800 in Meta spend. Suppose you've quietly had economic nexus in three states for four months and weren't collecting. If those three states account for a third of your orders, that's roughly 113 orders a month, and at an ~7% combined rate on $31 that's about $2.17 of uncollected tax per order.
Run the arithmetic: 113 orders × $2.17 × 4 months = about $980 you now owe the states out of pocket, because you can't retroactively bill customers who already checked out. On a store whose operating profit might be only $1,000–$1,500 in a good month, that back-tax wipes out most of a month's earnings.
Now flip it. Over-collect — charge tax in a state where you have no nexus — and you inflate prices, dent conversion on ad traffic you paid for, and hold money you may have to refund. Either error comes straight out of the number that actually matters: true per-order profit after every fee and tax.
This is exactly the figure most dashboards never compute, because sales tax collected sits in your payout looking like revenue. To see real margin per order you have to strip it back out — the same reason we treat this whole cluster as one system in the taxes and compliance guide.
Resale certificates: the other nexus-linked leak
Once you register for a sales tax permit to handle nexus, you unlock a resale certificate. Hand it to your POD supplier and your wholesale production orders become exempt — otherwise the supplier charges you sales tax on every print, and since you also collect from your customer, you pay tax twice on the same shirt.
Certificates aren't retroactive: suppliers won't refund tax on orders placed before approval. Set it up the same day you register for nexus. This connects directly to your 1099-K reporting threshold and, for sellers registering an entity first, to forming a US LLC from abroad.
How Victor keeps nexus from eating your margin
Victor is the AI employee inside PodVector AI. Victor is not a dashboard — he connects to your Shopify store, Meta Ads, Google Ads, your POD supplier (Printify, Printful, or Gelato), and Klaviyo, then computes true per-order profit that strips out fees and collected tax so you see real margin, not payout-inflated revenue.
When your order mix into a state starts approaching a threshold, that's a signal you need to register before you owe. Victor works from live data across those integrations and delivers reports to your Google Drive. He also drafts customer-support emails when tax questions come in. Put Victor to work on your store and stop finding out about nexus after you already owe it.
When you're ready to stop tracking states in a spreadsheet, our guide to Shopify sales tax automation covers the tooling that files and remits for you.
FAQs
Do I have to collect sales tax in every state?
No. You collect only in states where you have nexus — physical presence or sales past that state's economic threshold. Most operating stores have nexus in a handful of states, not all of them, and the list grows as you scale into new markets.
How do I know if I've crossed economic nexus in a state?
Track your sales and transaction counts into each state separately over a rolling twelve months, then compare against that state's specific threshold. The common bar is $100,000 or 200 transactions, but Texas and California use $500,000, per Avalara. Low-AOV POD stores usually trip the transaction count first.
Does Shopify handle sales tax nexus for me?
Only partly. On a normal storefront Shopify calculates and collects once you configure where you have nexus, but you still register, file, and remit yourself. The Shop app is the one exception where Shopify fully handles tax, as Craftybase explains.
What happens if I ignore nexus and don't collect?
The obligation doesn't disappear — you owe the uncollected tax out of your own pocket, plus possible penalties and interest, because you can't retroactively charge customers who already bought. That's why a growing store should watch per-state volume, not just total revenue.
Is nexus the same as income tax?
No. Nexus governs sales tax — money you collect from buyers and pass to states. Income tax is separate, and you owe it on your profit regardless. Sole proprietors also owe self-employment tax and usually quarterly estimates; see the taxes and compliance guide.
This is general information, not tax advice. Rules change and vary by situation — consult a licensed CPA or tax professional before acting.