Sales Tax Nexus: The Complete Guide for Multi-State Sellers

Imagine shipping a $50 candle from your home studio in Oregon to a customer in Florida. Seems harmless, right? Now imagine doing that 2,000 times in a year. Congratulations—you may have just triggered a sales tax obligation in a state you've never set foot in, with back taxes, penalties, and interest waiting if you don't register.

This is the reality of sales tax nexus in 2026. Since the Supreme Court's landmark South Dakota v. Wayfair decision in 2018, every state with a sales tax can require remote sellers to collect and remit—even without a single employee, office, or warehouse inside its borders. For small businesses selling across state lines, nexus isn't a theoretical concern. It's one of the fastest-growing sources of unexpected tax bills.

This guide breaks down what nexus is, how it gets triggered, the thresholds you need to know for 2026, and the practical steps to stay compliant without hiring an army of CPAs.

What Is Sales Tax Nexus?

Nexus is a legal term for a connection between your business and a state that is strong enough to obligate you to collect and remit sales tax there. Think of it as the state's answer to the question: "Do you have enough presence here that we can tax your sales to our residents?"

Before 2018, "presence" generally meant physical presence. You needed a storefront, an office, employees, or inventory in a state to trigger nexus. Then came South Dakota v. Wayfair, Inc., which upended 50 years of precedent and opened the door for states to impose sales tax obligations based purely on economic activity—revenue or transaction counts, no physical footprint required.

Today, every state with a general sales tax (45 states plus Washington D.C. and Puerto Rico) enforces some version of economic nexus. And most enforce physical nexus rules on top of that.

The Two Main Types of Nexus

Physical Nexus

Physical nexus is the traditional test. You establish it by having any of the following in a state:

• A business location: office, storefront, showroom, or warehouse
• Employees or contractors: including sales reps, installers, or remote workers living in the state
• Inventory: goods stored in a third-party warehouse or fulfillment center (this is huge for Amazon FBA sellers)
• Property: owned or leased real estate, equipment, or vehicles
• Affiliates: third parties earning commissions by referring customers to you
• Temporary activities: trade shows, craft fairs, pop-ups, or conventions—even short ones

The inventory trap is particularly important for e-commerce sellers. If Amazon stores your FBA inventory in a fulfillment center in Pennsylvania, you generally have physical nexus in Pennsylvania—whether you knew it or not.

Economic Nexus

Economic nexus is triggered by your sales volume into a state, regardless of whether you have any physical connection. The two most common triggers are:

• Revenue threshold: typically $100,000 in gross sales into the state over a 12-month period
• Transaction threshold: typically 200 separate transactions into the state over a 12-month period

In most states, crossing either threshold establishes nexus. In a few states, you must cross both.

Economic Nexus Thresholds by State in 2026

While the $100,000 / 200-transaction rule is the most common, thresholds vary significantly. Here's a snapshot of what to watch in 2026:

• Most common: $100,000 in sales OR 200 transactions
• Illinois (as of January 1, 2026): repealed its 200-transaction threshold. You only register if gross receipts exceed $100,000 over the preceding 12 months
• California and Texas: $500,000 in sales (no transaction threshold)
• New York: both $500,000 in sales AND 100 transactions required
• New Jersey: either $100,000 in sales OR 200 transactions
• Kansas: $100,000 in sales (no transaction threshold)
• Florida: $100,000 in sales (transactions not counted)

The trend in 2026 is clear: states are consolidating around a flat $100,000 revenue benchmark and dropping transaction-based triggers, which unfairly burdened sellers of low-priced goods. But don't assume—always verify the current threshold for any state where you're approaching the line.

Six Ways Small Businesses Accidentally Trigger Nexus

Physical and economic nexus are the two main categories, but within them are specific traps that catch small businesses off guard:

1. Remote Employees

Hiring a remote worker in Georgia means you now have physical nexus in Georgia—even if your headquarters is in Nevada and you've never visited the state. With the post-pandemic shift to distributed work, this is now the single most common accidental nexus trigger.

2. Amazon FBA Inventory

If you sell on Amazon and use FBA, Amazon decides where to store your inventory based on its logistics. That inventory can land in a dozen states you've never targeted, each potentially creating nexus. Marketplace facilitator laws (more on those below) have reduced this risk but haven't eliminated it—especially if you also sell through your own website.

3. Drop Shipping Relationships

When you drop-ship, the interplay between you, your supplier, and the customer can create nexus in the supplier's state, the customer's state, or both. Resale certificates typically cover the wholesale side, but you may still owe sales tax to the end customer.

4. Trade Shows and Pop-Ups

A weekend booth at a craft fair in Tennessee is a taxable event. Many states have specific rules for "temporary" sellers, and some will register you the moment you collect payment inside their borders.

5. Click-Through and Affiliate Marketing

If bloggers or influencers in a state refer customers to you for a commission, several states treat this as creating click-through nexus, even without physical presence.

6. Trailing Nexus

Here's a surprise: in some states, you keep collecting and remitting sales tax for months or years after your nexus-creating activity ends. Close a warehouse in Michigan on January 1? You may still owe Michigan sales tax collection duties through the rest of the year.

Marketplace Facilitator Laws: The Good News (Mostly)

If you sell on Amazon, Etsy, eBay, Walmart Marketplace, or similar platforms, there's a significant layer of relief. All 45 sales-tax states now have marketplace facilitator laws requiring the platforms themselves to collect and remit sales tax on your behalf for transactions they facilitate.

• Amazon: collects and remits sales tax for third-party sales in all applicable states
• Etsy: collects sales tax in every U.S. state with a statewide sales tax, plus Washington D.C. and Puerto Rico (45 jurisdictions covered automatically)
• eBay and Walmart: similar coverage across the board

But—and this is the critical "but"—marketplace facilitator laws only cover sales made through the marketplace. You still need to track and collect sales tax on:

• Sales through your own website or Shopify store
• Wholesale sales where the buyer doesn't have a resale certificate
• Cross-channel activity that might still create nexus

Many states also require you to register and file "zero returns" even if the marketplace is handling the actual collection. Ignoring registration because Amazon handles collection is a common mistake.

How to Determine Your Nexus Footprint

Here's a practical five-step audit you can do today:

Step 1: Map Your Physical Presence

List every state where you have:

• Offices, stores, warehouses, or other real property
• Employees (including remote workers)
• Contractors who operate in the state
• Inventory (including FBA, drop-shipper, or consignment stock)
• Property you own or lease

Step 2: Pull Your Sales Data by State

For the trailing 12 months, calculate:

• Total revenue by ship-to state
• Total transaction count by ship-to state

This is where good bookkeeping pays dividends. If your accounting system doesn't let you segment sales by destination state, you are flying blind.

Step 3: Compare Against Thresholds

For each state where you have sales, check the current economic nexus threshold. A free state-by-state chart from your state's department of revenue website or a reliable sales tax automation provider is sufficient for most sellers.

Step 4: Identify Your Marketplace vs. Direct Mix

For each state where you're close to or over threshold, identify how much of that revenue came from a marketplace that collects tax on your behalf versus your own channels.

Step 5: Prioritize

Start with the states where:

• You have clear physical nexus
• Your non-marketplace revenue alone exceeds the threshold
• You've been accruing liability for the longest

Compliance Steps Once You Have Nexus

Once you establish nexus in a state, the roadmap is straightforward in principle—though each state adds its own wrinkles:

1. Register for a sales tax permit. This is free in most states and required before you can legally collect tax.
2. Configure your cart or POS to charge the correct destination-based rate. Sales tax in most states is based on the buyer's location, not yours.
3. Collect tax on taxable sales. Remember that taxability rules vary: clothing is exempt in some states, groceries in others, SaaS in still others.
4. File and remit on the state's schedule. Monthly, quarterly, or annually depending on your volume.
5. Track exemption certificates. Wholesale and resale customers need valid exemption certificates on file.
6. Monitor nexus continuously. Your footprint changes every quarter as employees come and go and sales grow.

The Cost of Getting It Wrong

Ignoring nexus obligations is not a sustainable strategy. Most states impose:

• Failure-to-register penalties: often flat fees plus percentages
• Failure-to-file and failure-to-pay penalties: commonly 10% to 25% of the unpaid tax
• Interest: accruing from the original due date, often compounding monthly
• Back-tax liability: lookback periods can extend three to six years or longer if the state believes you willfully ignored the obligation

In extreme cases, states can revoke business licenses, file tax liens, or pursue collection through other states' courts. Voluntary disclosure agreements (VDAs) are available in most states and can limit the lookback period and waive penalties—but only if you come forward before the state finds you.

Keep Accurate Records from Day One

Sales tax compliance rewards preparation. The single biggest advantage you can give yourself is clean, segmentable transaction data: sales by ship-to state, by date, by channel, by product taxability category.

Accurate, auditable bookkeeping transforms nexus monitoring from a panic-driven annual scramble into a routine monthly review. It also makes voluntary disclosure, audits, and multi-state filings drastically easier when the time comes.

Simplify Your Financial Management

As your business grows across state lines, the stakes for accurate record-keeping only rise. Beancount.io provides plain-text, double-entry accounting that gives you complete transparency and control over every transaction—no black boxes, no vendor lock-in, and a ledger you can slice by state, channel, or category in seconds. Get started for free and see why developers, finance teams, and multi-channel sellers are switching to plain-text accounting.