What a nexus check tells you
Since South Dakota v. Wayfair (2018), a state can require an out-of-state seller to register and collect sales tax once its sales into that state cross a set threshold — no physical presence needed. That's economic nexus. The trap is that you can trip a threshold silently as you grow, and the back taxes, penalties, and interest for collecting late are yours to pay. A nexus check compares your actual sales into each state against that state's current threshold, so you learn where you owe before a state notice does it for you.
How the checker works
Add your states
Pull sales-by-state totals from Shopify, Amazon, or Stripe and enter them.
See where you crossed
Each state is checked against its live threshold. Triggered, approaching, or clear.
Get the rate
For states you've triggered, see the rate to collect and a clean summary.
The whole thing runs locally in your browser. There's no server round-trip and nothing to sign up for — it's the fastest honest way to see your exposure.
The thresholds it checks against
Thresholds aren't uniform, and they've been shifting. The common figure is $100,000 in annual sales into a state, but the big states set their own bars, and the old transaction-count tests are being phased out.
| Threshold | States (examples) |
|---|---|
| $100,000 | Most states use this as the sales threshold |
| $250,000 | Mississippi, Alabama |
| $500,000 | California, Texas, New York |
| No state sales tax | Delaware, Montana, New Hampshire, Oregon (Alaska has no state tax, but local jurisdictions may impose one) |
Transaction counts are disappearing. Nine states repealed their 200-transaction test between 2023 and 2026 — South Dakota, Louisiana, Indiana, North Carolina, Wyoming, Alaska, Utah, and Illinois, with Kentucky's repeal effective 1 August 2026 — moving to a dollar-only test. New York and Connecticut use an AND test, where you must meet both the dollar and transaction thresholds. Elsewhere, if a state still has two thresholds, crossing either one usually triggers nexus. The checker keeps these rules current so you don't have to track each state's law yourself. For the full breakdown, see the economic nexus by state guide.
After the check: monitoring, not a one-time snapshot
A single check tells you where you stand today. The harder part is that you keep selling, and next quarter you may cross a new state. That's what NexusRadar does beyond the free checker: it monitors economic nexus across all states continuously, alerts you before or when you cross a threshold, and gives you the rate to collect — for a flat $29/mo, with no per-filing fees. It deliberately doesn't file returns; it hands you or your bookkeeper a clean per-state summary to file from. If you want to understand the concepts first, the learn explainers cover the basics, and the cost calculator sizes what compliance tools would cost you.
Check your nexus now
Free, browser-only, no account. See every state where you need to register and collect.