Sales tax nexus determination means deciding whether a business has a sufficient connection with a state to create sales tax obligations. Review physical activity and economic activity separately, then document the applicable rule and effective date. A revenue threshold alone cannot answer the question. This guide provides a working assessment process for US sellers, rather than another table of headline thresholds.
Key takeaways
Inventory and people can require analysis even when sales are below an economic threshold.
Compare the state’s defined sales base with the correct measurement period.
Keep marketplace collection separate from the seller’s registration analysis.
Record the reason, source, effective date, and next action for every state.
Start with the legal seller and a dated fact inventory
Create one assessment file for each legal entity. Record its trading names, storefronts, marketplace accounts, payment accounts, and any recent acquisitions. A dashboard that mixes two companies can produce the wrong threshold result, while a dashboard that omits a new sales channel can conceal exposure. Identify which entity signs the customer contract and issues the invoice before comparing sales totals.
Next, list where the business has inventory, employees, premises, installation activity, contractors, or events. These are screening questions, not a declaration that every activity creates nexus everywhere. Ask operations and HR for the actual start and end dates. Preserve warehouse reports and agreements so the assessment can be reconstructed if business arrangements later change.
Test physical presence before relying on an economic safe harbor
Physical presence and economic nexus are separate routes to an obligation. Streamlined Sales Tax’s remote-seller guidance distinguishes remote sellers from businesses with physical presence. Review the destination state’s own guidance when inventory or personnel are present; do not assume that low sales provide protection.
For an internal review, use three labels: confirmed activity, confirmed absence, and facts missing. An unanswered warehouse-location question belongs in the third category. Give missing facts an owner and due date. If fulfillment stock moves between states, keep the historical movements rather than relying on today’s inventory snapshot. The assessment needs to explain the period under review, not just the current arrangement.
Build the economic nexus calculation from source orders
The state-by-state nexus guide explains why threshold definitions differ. Use the current official state rule to identify the amount, any transaction test, included sales, measurement period, and collection-start requirement. Store those fields separately. A single column marked threshold does not show whether the calculation is based on gross, retail, or taxable sales.
Export order-level sales with destination, date, channel, product classification, exemption reason, and refund references. Reconcile the extract to accounting before filtering it for nexus. Payment processor deposits are a poor substitute because fees and settlement timing can distort the sales base. Keep both the unfiltered ledger and the rule-specific calculation so a reviewer can trace each excluded amount.
Worked example: why two sales totals produce different decisions
Consider a hypothetical seller with $82,000 in direct sales and $31,000 in marketplace sales delivered to a state during the relevant period. Its combined destination sales are $113,000. If that state’s applicable rule includes both channels, reviewing only the $82,000 storefront figure understates the monitored amount. If a different rule excludes qualifying marketplace sales, the calculation changes. These amounts illustrate the method; they are not a statement of any state’s threshold.
Now add inventory held in that state. The reviewer must examine physical presence independently, even if the economic calculation stays below the applicable limit. Conversely, a marketplace collecting tax does not by itself answer whether the seller has direct-channel or reporting duties. Put each conclusion in a separate field: nexus, registration, collector, and return treatment.
Turn the assessment into a registration decision
Write a short conclusion for each state: facts tested, period covered, governing source, result, unresolved issues, and action date. Avoid a bare yes or no with no explanation. Useful operational statuses include monitoring, facts pending, adviser review, registration in progress, and registered. These are internal workflow labels, not legal classifications.
Where registration is required, coordinate the permit, collection configuration, first filing period, and responsible person. If the research suggests an obligation began in a prior period, obtain advice on historical exposure and remediation before assuming that registering today resolves it. For the subsequent process, use the sales tax permit article.
Maintain the decision when business facts change
Create a monthly review of revenue and a separate event-driven review for new inventory locations, hires, acquisitions, and channels. Set internal warning levels below the applicable threshold to allow time for research. A warning is a management control, not a statutory collection trigger. Keep historical rule versions when thresholds or their definitions change.
For each completed review, retain the data extract, calculation, source URL, date accessed, decision, and sign-off. Link the resulting registration to the return-filing workflow. A nexus assessment is useful only if the decision reaches checkout and the filing calendar. Confirm that both teams received it and that any effective-date mismatch is resolved.
Frequently asked questions
Is nexus determination the same as calculating sales tax?
No. Nexus determines whether a state connection creates obligations. Calculating tax then requires product taxability, sourcing, rates, exemptions, and registration details.
Can a marketplace report replace a nexus assessment?
No. It is evidence for one channel. Combine it with direct sales and physical-activity facts, then apply the state’s rules.
Should I register in every state with a customer?
A customer alone does not establish a universal registration rule. Assess the relevant state’s physical and economic nexus requirements and any other applicable rules.
Official sources
Reviewed against the following primary sources on Sep 18, 2026.