Sales tax basics
45 US states plus DC charge sales tax. Rates run 4–10%. Every state sets its own rules for when a non-resident business must register and collect.
Nexus — what triggers it
- Physical nexus: office, warehouse, employees or inventory in the state
- Economic nexus: sales above a threshold — usually $100,000 or 200 transactions per state, per year
- Marketplace facilitator: if you sell only on Amazon, Walmart or eBay, the marketplace collects for you in every state
Marketplace facilitator laws
Since 2018 every state with sales tax passed a Marketplace Facilitator Act. Amazon, Walmart, Etsy, eBay and TikTok Shop now collect and remit sales tax on your behalf for those channels. You still owe on direct sales through Shopify or your own site.
When to register
Register in a state the moment you exceed its economic nexus threshold, or the same month you place inventory there. Late registration is common but expensive — states charge back-taxes plus interest.
Sales tax software
- TaxJar — best for Shopify + Amazon aggregations
- Avalara — enterprise-grade automation
- Shopify Tax — native to Shopify checkouts
- Numeral — modern software with hands-on support
Frequently asked questions
Usually no filings are needed in Amazon-only states unless you cross physical nexus. Shopify and direct sales are your responsibility.