US Sales Tax Nexus for E-commerce: A State-by-State Overview
Since South Dakota v. Wayfair, US sales tax is a compliance nightmare for online sellers. Here's how to figure out where you owe tax.
8 min read · 9 February 2026
Physical nexus vs economic nexus
Physical nexus is created by employees, inventory (including in Amazon FBA warehouses), offices or contractors in a state. Economic nexus is created by sales volume alone — no physical presence required.
Most states use a $100,000-in-sales or 200-transactions threshold, measured over the current or previous calendar year. California and Texas use $500,000. New York uses $500,000 and 100 transactions.
Marketplace facilitator laws
If you sell only through Amazon, Etsy or eBay, those marketplaces collect and remit sales tax on your behalf in most states. But marketplace sales still count toward your economic nexus threshold in some jurisdictions — meaning your direct website sales in those states become taxable earlier than you expect.
This is one of the most misunderstood rules in US e-commerce. Getting it wrong creates back-tax exposure that grows quietly.
When to register and how to catch up
Register within 30 days of crossing a state's threshold. For past exposure, most states offer Voluntary Disclosure Agreements that cap the lookback period (typically 3–4 years) and waive penalties in exchange for coming forward voluntarily.
NovaLedge runs a nexus study, registers you in each state you have exposure in, and files monthly, quarterly or annual returns depending on volume.