What are the economic-nexus thresholds, and when exactly do I have to register?

The most common pattern is a revenue threshold centered on $100,000, sometimes paired with a 200-transaction alternative — the two safe harbors from the South Dakota law the Supreme Court upheld in Wayfair. But the variations matter: some larger states set a much higher dollar threshold (several use $500,000), and some measure only taxable sales rather than gross sales. Thresholds are measured state by state, each on its own window and sales definition.

A clear 2024-2026 trend is states removing the 200-transaction threshold and keeping only the dollar threshold — which actually reduces the number of small-volume sellers caught, because hitting 200 low-value orders no longer triggers nexus on its own. Several states have dropped the transaction test in recent years on their own effective dates. Treat any specific number — including these — as a starting point to verify against the current state source, because the rules change every legislative session.

Nexus is the trigger to register. Once you cross a state's economic threshold (or establish physical presence, such as inventory in the state), you should register for that state's sales-tax account, then begin collecting on taxable sales to that state and file on the assigned frequency. The exact date collection must begin after a threshold is crossed differs by state, so track the date you cross in each state. The order is important: register before you collect.