Rules
Sales tax nexus for US online sellers, when to register in other states
Affordable venture planning? Economic nexus thresholds, Wayfair rules, state registration deadlines, and marketplace facilitator laws for US online sellers.
What to take away
- An affordable venture that sells online can create sales tax duties in other states once it crosses an economic nexus threshold.
- The Wayfair decision let states tax remote sellers, so physical presence is no longer the only trigger.
- Most states use a sales amount, a transaction count, or both, and the clock usually runs on the previous or current calendar year.
- Marketplace facilitator rules often push collection onto Etsy, Amazon, or eBay for sales made on their platforms.
- Registration deadlines vary, and waiting can mean back taxes plus penalties from the first day you crossed the line.
- Keep clean records by state, because a multi-state audit asks for dates, amounts, and platform reports.
What Wayfair changed for small US online sellers
The Wayfair decision in 2018 removed the physical presence rule for sales tax collection. Before that case, a seller generally needed a store, warehouse, office, or employee in a state to be required to collect. After Wayfair, a state can require collection based on economic activity alone, which is why economic nexus thresholds now matter to small stores.
The Supreme Court did not set one national threshold. It allowed states to set their own, within reason, so the rules differ by state. A seller in Texas can owe nothing to California until a threshold is crossed, then owe California tax on later sales. That is the practical shift: tax duties follow sales, not just buildings.
For a seller testing an affordable venture, this can feel like a sudden map of obligations. The work is not impossible. It is mostly a matter of watching two numbers, sales and transactions, then registering where the numbers require it.
The IRS business tax center is a useful starting point for federal obligations, which are separate from state sales tax. Businesses | Internal Revenue Service
Physical presence still matters. If you store inventory in a third-party warehouse in another state, or if a contractor works from a home office there, you may have nexus even below an economic threshold.
Many small sellers use a home address plus a marketplace warehouse, so they should check both tests. A warehouse in New Jersey can create nexus in New Jersey regardless of sales volume.
A common error is to assume that one registration covers everything. It does not. Sales tax registration is state by state, and sometimes local rates apply on top of state rates. Sellers who treat the map as one big market often undercollect in some states.
The same three mistakes show up often enough to be worth reading before you map your own obligations. same three mistakes
Economic nexus thresholds state by state and how to read them
An economic nexus threshold is the sales amount or transaction count that triggers a collection duty in a state. States publish their own figures, and those figures change. The safe method is to check the state revenue department page for each state where you sell, not a blog list that may be out of date.
Most states use a sales amount alone. Some use a transaction count alone. Others use either, meaning a small seller with many low-priced orders can cross on count before crossing on dollars. That last pattern catches handmade sellers and sticker shops, where a $4 order still counts as one transaction.
The measurement period also varies. Many states look at the previous calendar year. Some look at the current year and require registration once you cross during that year. A few look at a rolling twelve months. Your accounting system should be able to report sales by state and by year, or you will be guessing.
| State | Common threshold pattern | What to watch |
|---|---|---|
| California | Sales amount, no transaction count | Higher dollar trigger than many states |
| Texas | Sales amount | Safe harbor for small totals |
| Florida | Sales amount | Registration after crossing |
| New York | Sales amount and transaction count | Two tests, both can trigger |
| Washington | Sales amount | No transaction count test |
| Colorado | Sales amount | Home rule cities add local rules |
| North Carolina | Sales amount | Registration with the state |
| Illinois | Sales amount or transaction count | Retailers' occupation tax applies |
Read the table as a pattern guide, not as current law. Figures move, and a state can change its threshold in a budget session. The Federal Register money topics page tracks federal finance rules, not state sales tax, but it is a reminder that tax rules move through official channels first. Federal Register :: Money
When you read a state page, look for four things: the sales figure, the transaction figure if any, the measurement period, and the registration deadline. Write those four items in a spreadsheet row for each state. That row becomes your nexus checklist, and it is far cheaper than a surprise assessment.
Registration deadlines and back-tax risk after crossing a threshold
State registration deadlines are not uniform. A state may require registration within a set number of days after the month you cross, or by the first day of the next month, or before your next filing period. Some states give a short window, others a longer one.
The deadline usually runs from the date the threshold was crossed, not from the date you noticed.
Back-tax risk is the real cost of waiting. If you cross a threshold in March and register in September, the state can assess tax on sales from the trigger date forward. Interest and penalties stack on top. In a state with local rates, the assessment can include local tax you never collected.
Voluntary disclosure programs exist in many states for sellers who come forward before an audit. They can reduce penalties, though rules differ. They are not a loophole for sellers already under review. If you find that you crossed a threshold a year ago, talk to a tax professional before filing a registration you cannot unwind.
Registration itself is usually a state revenue department process, not a Secretary of State filing. You may need both. Forming an LLC or corporation is a business registration, while a sales tax permit is a tax registration. The USAGov small business portal outlines general registration steps for new businesses. Small business | USAGov
Before multi-state registration, get an employer identification number if you do not have one. An EIN is free from the IRS and separates your business tax identity from your Social Security number. Banks and state forms often ask for it. Get an employer identification number | Internal Revenue Service
Marketplace facilitator rules and who collects the tax
Marketplace facilitator rules make the platform responsible for collecting and remitting sales tax on marketplace sales in most states. If you sell on Etsy, Amazon, eBay, or Walmart, the facilitator generally collects on those transactions. That does not erase your own website sales, which remain your responsibility.
This split creates a common trap. A seller sees that Etsy collects tax and assumes no registration is needed anywhere. Then direct website sales cross a threshold, and the seller is unregistered. The fix is to track marketplace sales and direct sales separately in every state.
Some states still require a marketplace seller to register even when the facilitator collects. The registration may be for reporting or for direct sales. Read the state guidance for marketplace sellers, not just the general threshold page. Marketplace facilitator laws also affect whether your gross sales count toward a threshold, or only your direct sales.
A practical setup is to keep one spreadsheet tab per channel. One tab for marketplace sales, one for your own store, and a summary tab that adds only the sales that count in each state. If you sell handmade goods, platform fees change the math of which channel is worth the compliance work. etsy fees vs shopify
Facilitators can also change their own reporting. Keep the monthly reports they provide, because those reports are the cleanest proof of what was collected and when. If a state asks about a period, a platform report answers faster than a bank statement.
A registration decision checklist for a growing storefront
Use this registration checklist when sales grow or when you add a new state. The goal is a decision, not a permanent research project. Run it quarterly, and after any month with unusual volume.
- List every state where you had sales in the last twelve months
- Pull gross sales and transaction counts by state from your platform and store reports
- Compare each state total to that state's current economic nexus threshold
- Mark states where you sell through a marketplace facilitator and note who collects
- Check whether inventory, staff, or contractors create physical presence in any state
- Confirm the registration deadline and the measurement period for each triggered state
- Register, then set a calendar reminder for the first filing due date
Step by step, the process looks like this.
- Export sales by state for the previous calendar year and the current year to date.
- Remove or flag marketplace sales if the facilitator collects in that state.
- Compare the remaining totals to each state threshold.
- Register in triggered states and apply for any local accounts the state requires.
- Turn on tax collection in your store for those states, then file on schedule.
Two more checks belong in the routine. First, confirm your business registration is active in your home state, since a lapsed entity can complicate tax registration. Second, keep an eye on federal business rules that affect sellers, such as labeling and advertising requirements. Federal Register :: Business & Industry
If you are still choosing what to sell, the threshold map should influence the plan. A high-ticket product crosses dollar thresholds with fewer orders. A low-ticket product crosses transaction thresholds faster. The honest guide to online business ideas covers how product choice shapes the back office. honest guide to online business ideas
A worked example makes the timing clear. Suppose a Colorado seller has $80,000 in direct website sales to Texas customers in the previous calendar year and no marketplace sales there. If Texas uses a sales threshold below that figure, the seller should have registered and collected from the point of crossing.
The fix is registration plus a review of back tax exposure, not a wait-and-see approach.
Numbers alone do not decide the business. Margin, shipping, and return rates decide whether a state is worth serving at all. A seller can also choose to stop selling into a state, though platforms make that harder. Treat the registration decision as part of pricing, not as an afterthought. online business ideas metrics
Recordkeeping that survives a multi-state audit
A multi-state audit is mostly a records test. The state wants to see sales by date, destination, and channel, plus proof of what you collected and remitted. If your records cannot separate marketplace sales from direct sales, the audit becomes a reconstruction, and reconstructions favor the state.
Keep source reports. Download monthly marketplace reports and store reports as PDFs or spreadsheets. Store them in a folder named by year and state. Do not rely on the platform to keep them forever, because access can change after you close an account.
Reconcile quarterly. Match your tax collected to your tax remitted in each state. A small difference is normal, but an unexplained gap invites questions. Note any refunds, exemptions, or resale certificates in the same file.
Keep registration documents together. Your sales tax permit, your EIN letter, and your state business registration belong in one folder. If you expand into Canada later, the process is different, and the paperwork you keep now still helps. register a side hustle
Set a retention rule and follow it. Many states allow audits going back several years, so keep records at least that long. Cloud storage is cheap, and a labeled folder is faster than an email search during an audit.
Common questions
Do I need to register in every state where I sell? No. You register where you have nexus, which usually means crossing an economic nexus threshold or having physical presence. Marketplace facilitator rules can remove the collection duty for platform sales in many states.
What is the Wayfair decision in simple terms? It is the 2018 Supreme Court ruling that let states require sales tax collection from remote sellers based on economic activity. Physical presence is no longer the only trigger.
How do I find my state's economic nexus threshold? Check the state revenue department website, not a third-party list. Record the sales figure, transaction figure, measurement period, and registration deadline for each state.
Who collects sales tax on Etsy or Amazon sales? Under marketplace facilitator rules, the platform generally collects and remits on those sales. Your own website sales are still yours to handle, and some states still require a seller registration.
What happens if I register late? The state can assess back tax from the date you crossed the threshold, plus interest and penalties. Some states offer voluntary disclosure programs that reduce penalties if you come forward before an audit.
Do I need an EIN before registering in another state? Many state forms and banks ask for one, and it is free from the IRS. Getting an EIN before multi-state registration keeps your business identity separate from your Social Security number.
