Adding a sales channel can change your sales tax obligations even when that channel collects tax for you. A marketplace may handle tax on its orders while those sales still count toward a state's registration threshold. Moving inventory to a new warehouse can create a separate reason to register. Selling wholesale adds exemption documentation to the process.
For a finance team managing several channels, the challenge is keeping those obligations connected. You need to know where the business needs to collect, who handles each sale, and whether the amounts collected, filed, and paid tie back to your books correctly.
This guide covers US sales tax for brands selling physical products through a mix of their own stores, marketplaces, wholesale, and retail. It follows five jobs: identifying exposure, registering, calculating tax, filing and remitting, and reconciling the result.
In this guide
- Who collects sales tax across your channels
- Know where you have exposure
- Register and establish when collection must begin
- Calculate tax correctly across channels
- File and remit across channels
- Reconcile sales tax and support your close
- Changes that should trigger a tax review
- When to automate and what to look for
- Frequently asked questions
- Ten questions to check your sales tax setup
Who collects sales tax across your channels
Your responsibilities depend on where you have exposure, what you sell, and how the transaction happens. Nexus is the legal term for the connection that lets a state impose tax obligations on your business. We call it exposure, because that is what it is to your P&L. It can arise from physical presence or sales activity, as explained below.
This table describes responsibility. Software or a service provider may perform the work, but your team still needs to confirm what is covered. A 3PL is a fulfillment arrangement; using one does not, by itself, transfer your sales tax responsibilities.
1. Know where you have exposure
Your brand may have exposure in a state through physical presence, economic activity, or both. Exposure can create registration and collection requirements, subject to the state's rules and any applicable exemptions.
Physical presence
An office, employees, a retail location, or inventory in a warehouse can create exposure through physical presence. That includes inventory stored by a third-party logistics provider. Review the tax implications before inventory moves or a new location opens, even if sales into the state are low.
Marketplace fulfillment requires a closer look. In Illinois, for example, inventory used exclusively to fulfill orders through a qualifying marketplace does not create physical presence for the seller under the state's guidance. Inventory used for the seller's own orders, or both types of orders, does. The state's marketplace and inventory guidance explains the distinction.
Economic presence
Economic presence can require a remote seller to register and collect tax because of its sales into a state, even without a physical presence there.
Check more than the dollar threshold. Each state defines which sales count, the measurement period, and when registration and collection must begin. Some states also use a transaction threshold.
New York, for example, requires a remote seller to evaluate whether it exceeded both $500,000 in gross receipts from sales of tangible personal property delivered into the state and 100 sales during the immediately preceding four sales tax quarters. Those quarters differ from calendar quarters. See New York's registration requirements.
Which sales count
A marketplace's collection of tax does not automatically remove those sales from your threshold calculation. Exempt sales and wholesale sales may also count, depending on the state.
Consider a brand with $60,000 in direct sales and $50,000 in marketplace sales delivered into Washington during the same calendar year. Washington includes both in its gross receipts calculation, so the combined $110,000 exceeds its $100,000 threshold. The brand must evaluate its registration and direct-sale collection obligations even if the marketplace handled tax on marketplace orders. Washington also has business and occupation tax requirements that need separate attention.
What to do: Maintain sales data by destination state across every channel, along with a current inventory-location list. Monitor each state using its own threshold definitions and measurement period. Set alerts before thresholds are reached, and review new channels or fulfillment locations before launch.
2. Register and establish when collection must begin
Once you identify an obligation, determine the applicable registration deadline and collection start date. Complete the required registration before collecting tax. Delaying registration does not remove an obligation that has already arisen.
Keep a record of each registration, account number, effective date, filing frequency, and first return due date. Connect those details to your checkout settings and filing process so registration leads to the correct operational changes.
Marketplace-only sellers need a separate check. Some states provide registration relief when a qualifying facilitator handles all sales. For example, California generally does not require a seller to register if all its retail sales of merchandise are facilitated by a marketplace facilitator registered with the state. See California's marketplace guidance.
If you already missed a threshold
Reconstruct when the obligation began and which sales were affected. A current registration does not, by itself, resolve earlier periods.
Have a tax professional assess the appropriate sequence for registration, historical filings, and any voluntary disclosure application. A voluntary disclosure agreement may limit the lookback period or reduce penalties, depending on the state and your circumstances. Prior contact with a state can affect eligibility, so evaluate the options promptly before taking steps that could close them off. The Multistate Tax Commission's program explains how its process works.
What to do: Keep one registration calendar with an owner for each next step, including any historical periods that still need resolution.
3. Calculate tax correctly across channels
Accurate calculation depends on the transaction's location, the product, and any applicable exemption. A default rate or product category can miss differences within your catalog.
Rates and product taxability
For many interstate deliveries, the customer's delivery address determines the applicable tax rate. Use the full address rather than a ZIP code alone, and account for the sourcing rules that apply to in-state sales, pickups, and POS transactions.
Assign product categories that reflect what you sell. Clothing, supplements, food, and personal-care products can receive different treatment across states. Even an exemption may vary locally: eligible clothing and footwear priced below $110 are exempt from New York state sales tax, but local exemptions vary. See New York's clothing guidance.
Shipping and promotions
Shipping and handling need their own rules. Whether a charge is taxable can depend on the underlying goods, how the charge is stated, and the delivery arrangement. Separately stating shipping is not a universal exemption. California, for example, places conditions on excluding delivery charges, including limits tied to actual delivery costs. See California's shipping guidance to learn more.
Before launching promotions, review how your checkout treats discounts, gift cards, and bundles containing products with different tax treatment.
Wholesale exemptions
A business customer is not automatically tax-exempt. Determine whether the purchase qualifies for resale or another exemption and obtain the documentation accepted by the relevant state. Validate and retain certificates, and refresh them when required. The Multistate Tax Commission's certificate guidance explains common resale-documentation issues, and our exemption certificate guide covers the rules state by state.
What to do: Test representative orders from your actual catalog, including exempt products, wholesale customers, shipping charges, and promotions. Confirm which system calculates tax for each channel and who maintains its settings.
4. File and remit across channels
Filing turns transaction records into the returns and payments required by each jurisdiction. Your filing calendar should reflect the frequency assigned to your business, applicable due dates, and any prepayment requirements.
Multichannel filing starts with complete sales data, but each jurisdiction determines what belongs on its return. Some require marketplace sales to be reported and deducted; others exclude them. Illinois, for example, instructs sellers to leave sales handled by a collecting marketplace off their own Form ST-1. Follow the state's reporting instructions.
Do not assume one state return covers every obligation. Some local jurisdictions administer their own taxes. Colorado offers a consolidated filing system for state-collected taxes and participating local jurisdictions, but your setup still needs to account for any remaining local requirements. See Colorado's filing-system guidance.
Returns and refunds
Refunds need to reach both your sales records and your tax process. If a customer returns a $100 product that carried $8 of tax, track the $100 sales reversal and $8 tax refund separately. Record whether the tax was already remitted and how any permitted credit or adjustment is reflected in a return. Apply the jurisdiction's rules for supporting documentation and timing.
Also check whether a return is required when no tax is due. In New York, for example, a registered business that remains registered must continue filing for each reporting period even when it makes no sales.
What to do: Before submitting returns, confirm that every relevant channel is accounted for, marketplace tax is separated correctly, and refunds and exemptions have supporting records. Keep filing confirmations and payment records together.
5. Reconcile sales tax and support your close
Reconciliation connects your sales records, tax returns, payments, and general ledger. It lets you explain the sales tax payable balance at month-end and find differences that need investigation.
Collected tax and payments will not always match within the same month. A payment may settle a prior period, a quarterly return may not yet be due, or a prepayment may affect the balance. An unexplained difference needs investigation; it is not automatically an underpayment or overpayment.
Review differences such as:
- Marketplace-collected tax mistakenly included in your own remittance
- Refunds recorded in the store but missing from the tax records
- A channel or group of orders omitted from a filing
- Exempt sales without the required documentation
- Differences between checkout calculations and the amounts reported
Keep enough detail to trace a balance back to the underlying transactions and explain adjustments. That makes the close easier to review and gives you a clearer starting point for responding to a tax notice or audit request.
Anrok runs all five jobs on one platform, including reconciliation, which no other tax engine has built in. It compares transactions, returns, and payments with your general ledger, and the reconciliation documentation explains how filing timing and payments affect those balances.
What to do: Make reconciliation part of the monthly close. Assign an owner, document unresolved differences, and track them through resolution.
Changes that should trigger a tax review
Revisit your setup when the business changes:
- A new 3PL or inventory location: Assess exposure and registration requirements before inventory moves.
- A new marketplace: Confirm who collects, how sales affect thresholds, and how orders enter your reporting.
- A wholesale launch: Build certificate collection and validation into customer onboarding.
- A retail location or pop-up: Review permits, local tax rules, and POS settings before the first sale.
- Peak season: Check states approaching thresholds, promotional tax settings, and the process for returns after the season ends. See our peak season sales tax checklist.
- International expansion: Review the destination's VAT, GST, and import requirements separately from US sales tax.
When to automate and what to look for
Consider dedicated tax software when manual work makes it difficult to keep obligations current or explain your balances. Warning signs include repeatedly combining channel exports, discovering missing registrations late, and carrying unresolved tax differences from one close to the next.
Evaluate providers against your actual setup: every channel and inventory location, the move from exposure monitoring into registration and collection, product taxability and exemptions, state and local filings including marketplace reporting, refunds and reconciliation to your books, and access to tax specialists when a notice arrives. Our guide to the best sales tax software for ecommerce brands compares the options against those criteria.
Anrok for ecommerce runs exposure monitoring, registration, filing, remittance, and reconciliation on one platform, with tax specialists available for questions about your setup. Depending on your platform, it works alongside your existing checkout tax engine or provides calculation directly. Review your channel mix with our team to confirm coverage and data requirements.
Frequently asked questions
Do I have to collect sales tax on online sales?
Yes, on taxable sales in every state where you have exposure and the collection obligation has begun, unless a marketplace facilitator or another party is responsible under the law. Registration is a required step in that process; postponing it does not postpone an existing obligation. Five states have no statewide sales tax: Alaska (local taxes apply), Delaware, Montana, New Hampshire, and Oregon.
Does Amazon collect sales tax for me?
Yes, on Amazon marketplace orders, under marketplace facilitator laws. That does not cover orders placed through your own store, even if Amazon fulfills them. Review any remaining registration and reporting duties, and whether marketplace sales count toward your thresholds.
Does Shopify handle sales tax for me?
Partly. Shopify calculates tax at checkout based on the settings and registrations you configure, but tax calculation and tax filing are separate functions, and a calculated amount at checkout does not establish that registrations and returns are complete. Confirm what your active services cover and how sales outside Shopify are handled. Shopify's tax liability guidance explains the merchant's responsibilities.
Is shipping taxable?
In some states, yes. The answer turns on the state, whether the goods are taxable, and how the charge appears on the invoice. Separately stating shipping matters in many states, but it does not guarantee an exemption.
Do marketplace sales count toward economic nexus?
In many states, yes. Washington, for example, counts marketplace sales toward its $100,000 threshold even though the marketplace collects the tax. States differ in how they treat marketplace sales, wholesale sales, and other exempt transactions, so apply each state's definition rather than using direct-store revenue alone.
How often do I file sales tax returns?
Monthly, quarterly, or annually, based on the filing frequency each jurisdiction assigns you. Check for separate local returns, prepayments, and changes to your assigned frequency as the business grows.
Ten questions to check your sales tax setup
- Which states have you crossed a registration threshold in, using each state's sales definitions and measurement period?
- Where are your employees, retail operations, and inventory located?
- Are required registrations complete, with the correct collection start dates?
- Which channels collect and remit for you, and what responsibilities remain?
- Are product categories and exemptions configured correctly for your catalog?
- Are shipping, discounts, bundles, and refunds handled correctly?
- Do exempt sales have the required supporting documentation?
- Does your filing calendar cover every required state and local return and payment?
- Can you reconcile tax transactions, returns, and payments to the general ledger?
- Who owns unresolved differences and reviews changes to the business?
If answering these questions means chasing several exports and rebuilding the same spreadsheet each month, it may be time to connect the process. Book an Anrok demo to see how registration, filing, and reconciliation can work together for your business. One platform, full sales tax compliance.
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