Free sales tax nexus tracker: find out you're over the line before the state does.

Where nexus came from

Before 2018, a state generally could not force you to collect sales tax unless you had a physical presence there — an office, a warehouse, an employee. South Dakota v. Wayfair (2018) changed that: the Supreme Court upheld South Dakota's right to require collection based purely on economic activity in the state. Within a few years, nearly every state with a sales tax had an economic nexus law. Physical presence still creates nexus too — the two stack, so a warehouse in one state and $120,000 of sales into another can mean two registrations.

Why the thresholds are not the same everywhere

South Dakota's original formula — $100,000 in sales or 200 transactions — became the template most states copied. But each state sets its own figures. Most use $100,000. Alabama and Mississippi use $250,000. California, Texas and New York — the three largest state economies — use $500,000. Five states have no statewide sales tax at all (Alaska, Delaware, Montana, New Hampshire and Oregon), so there is no threshold to cross, though local taxes can still apply in Alaska.

The transaction-count test is disappearing

The original Wayfair formula had two triggers: a dollar amount or a transaction count, usually 200. That second test is being repealed state by state — Illinois dropped it on 1 January 2026, following Indiana (2024) and Wyoming (2024). The direction of travel is clear: the dollar threshold is becoming the only test that matters. A few states still keep a count test, and New York is the trickiest of all — it requires both $500,000 and more than 100 transactions before nexus attaches.

The measurement period matters as much as the number

Crossing a threshold is not just about the figure — it is about the window it is measured over, and windows differ. California looks at the preceding or current calendar year; Texas uses the preceding twelve calendar months; New York uses the preceding four sales-tax quarters. A heavy fourth quarter can trip a rolling-basis state months before a calendar-year state would flag you, which is why a single annual check is not enough.

Marketplace sales still count toward the threshold

Sell through Amazon, eBay or Etsy and marketplace facilitator laws mean the platform collects and remits tax on those orders in most states. But your direct sales — Shopify, WooCommerce, Stripe — remain your responsibility, and in most states marketplace sales still count toward the threshold maths even when the marketplace remits. That is the classic trap: sellers look at one channel, decide they are under, and miss that the others pushed them over months ago.

What late registration costs

States can assess back taxes from the date you first crossed the threshold, plus interest and penalties — and enforcement is increasingly automated, with states matching marketplace and payment-processor data against registration records. Voluntary disclosure agreements can limit the lookback period, but they are far cheaper to enter before the state finds you. The cheapest compliance strategy is knowing the crossing date while it is still in the future.

Commonly published 2026 figures, last verified October 2026. Tax rules change and measurement periods vary — verify with your tax advisor before registering. This page monitors; it is not tax advice.