Ecommerce accounted for 17.1% of total US retail sales in Q2 2026, up from 16.3% in the same quarter a year earlier, according to Shopify's 2026 sales tax guide. That growth means more small sellers are crossing sales tax thresholds they may not have hit before, making compliance a pressing operational issue rather than a background concern.
Why Nexus Determines Your Collection Duty
In the US, three factors determine what a seller owes at tax time: where the business has nexus, whether the product is taxable, and where the order ships. Nexus can be physical, through an office, warehouse, or employee, or economic, by exceeding a state's sales or transaction threshold. Once a seller meets a state's criteria, collection of sales tax on eligible orders shipped there becomes mandatory. There is no federal standard that overrides this state-by-state framework.
Washington, DC, and 45 states collect sales and use tax at the state level. Many local jurisdictions, including cities, counties, and special districts, layer their own rates on top. Alaska is a notable edge case: the state itself levies no sales tax, but some local jurisdictions within Alaska still impose their own local sales taxes, so sellers cannot assume a zero-rate applies statewide.
Source: Shopify
Cart Abandonment and the Checkout Tax Problem
Compliance also touches conversion rates directly. According to data cited in Shopify's guide from the Baymard Institute, 40% of US online shoppers named extra costs at checkout, including taxes, shipping, and fees, as their most common reason for abandoning a cart. Sellers can choose to build tax into listed prices to reduce checkout sticker shock, but doing so raises the displayed price, which can hurt competitiveness when price is a primary differentiator. Neither approach is universally right; the choice depends on margin structure and customer expectations.
Inflation context matters here too. The Bureau of Economic Analysis tracks the core PCE price index, the Federal Reserve's preferred inflation gauge, which measures what US consumers pay for goods and services excluding food and energy. When underlying inflation remains elevated, additional checkout costs like sales tax carry more weight in purchase decisions, reinforcing why sellers need a clean, accurate tax line rather than a surprise total.
Business Structure Affects Registration and Liability
How a seller is organized legally shapes sales tax obligations in practical ways. LLCs and corporations often face different registration and reporting requirements than sole proprietors. Some states require registration for a sales tax permit under the legal entity name, and sellers operating across multiple states may need to file separately for each entity. Forming an LLC or corporation can offer personal liability protection, but it does not eliminate the responsibility for accurate collection and remittance. Errors, including failure to collect or to remit on time, can trigger fines regardless of structure.
For sellers handling product and service sales together, complexity increases further. Service tax rules vary widely by state, with no federal standard. What is taxable in one state may be fully exempt in another, so sellers mixing digital or service offerings with physical goods face a patchwork of obligations that requires state-by-state review.
Source: NerdWallet
What Happens If You Skip Collection
Sales tax has a built-in enforcement backstop: use tax. If a seller does not collect sales tax at the time of purchase, the buyer technically owes use tax directly to the state. In practice, states increasingly pursue sellers rather than individual buyers, and automated tools have made audit exposure more real for ecommerce businesses at any scale. Keeping accurate tax records and filing returns on a regular schedule with each relevant state is the baseline requirement once nexus is established.
For ecommerce bookkeeping purposes, sellers should ensure their accounting software can separate sales tax collected from revenue, since remitted tax is not business income. Platforms like Shopify offer built-in tax collection tools that apply rate and regulatory changes automatically, which reduces manual reconciliation errors that can complicate quarterly filings.
Final Thought: With ecommerce now at 17.1% of US retail and nexus rules applying in 45 states plus DC, small online sellers who have not audited their sales tax exposure recently are taking on measurable compliance and financial risk.