When Do You Need to Start Collecting Sales Tax

Your Home State: Day One

Your sales tax obligation in your home state begins on the first day you make a taxable sale. Physical nexus exists from the moment your business has a presence in the state, which includes your home, office, warehouse, or any other business location. If you are based in a state with a sales tax, register for a permit and start collecting before you make your first sale.

Many new ecommerce sellers skip this step, either because they do not realize they need a permit to collect or because they plan to "figure it out later." Every sale you make to a customer in your home state without collecting tax creates a liability that you owe out of pocket. If you sell $10,000 worth of products to in-state customers in your first three months without collecting tax, and your state's average rate is 8%, you owe $800 to the state plus potential penalties for not registering. Register early, preferably before you launch your store.

States Where You Store Inventory: Immediately

If you use a third-party fulfillment center, warehouse, or Amazon FBA, you have physical nexus in every state where your inventory is stored, starting on the first day your inventory arrives at that location. For FBA sellers, this can mean nexus in 10 to 20+ states the moment you send your first shipment to Amazon, because Amazon distributes inventory across its nationwide fulfillment network.

Identifying which states hold your FBA inventory requires checking Amazon's inventory placement reports in Seller Central. Once identified, register for sales tax permits in each state and enable collection. Note that marketplace facilitator laws mean Amazon handles tax on your Amazon orders, but if you also sell through your own Shopify or WooCommerce store, you need to collect on those direct orders in every state where your FBA inventory creates physical nexus.

Economic Nexus: When You Cross the Threshold

For states where you have no physical presence, your collection obligation begins when you cross the state's economic nexus threshold. The timing of when collection must begin after crossing the threshold varies by state. The most common approaches are collection must begin on the first transaction after the threshold is crossed (immediate), collection must begin on the first day of the month after you cross the threshold (next month), collection must begin on the first day of the quarter after you cross the threshold (next quarter), or the state gives you 60 to 90 days to register and begin collecting.

Some states, including Pennsylvania and Oklahoma, apply the obligation retroactively to January 1 of the year in which the threshold is crossed. If you cross the threshold in August, you technically owed tax on all sales in that state from January through July. In practice, states with retroactive dates often do not aggressively enforce the pre-trigger liability, especially for sellers who voluntarily come into compliance, but the theoretical exposure exists.

How to Know If You Are Already Late

If you have been selling online for more than a year and have not reviewed your nexus obligations, there is a meaningful chance you are already late in one or more states. Pull your sales data by ship-to state for the current year and the prior full year. Compare your totals against each state's threshold. If you crossed a threshold at any point during either year, you should already be registered and collecting in that state.

Common scenarios where sellers discover they are late include growing past $100,000 in total sales and not realizing that some individual states were crossing thresholds, starting Amazon FBA without understanding that inventory creates physical nexus, selling through multiple channels (Shopify plus Etsy plus Amazon) without aggregating sales across channels for nexus analysis, and being a long-established business that predates the 2018 Wayfair decision and never revisited nexus obligations after economic nexus became law.

Being late is common and fixable. The worst action is to continue ignoring the obligation. Every additional day of non-compliance increases your liability. The best action is to register promptly and consider filing voluntary disclosure agreements for states with significant back-tax exposure.

Proactive vs Reactive Registration

Proactive registration means registering for a sales tax permit and beginning collection before you technically cross the nexus threshold, anticipating that you will cross it based on your sales trajectory. If you have $75,000 in sales to a state with a $100,000 threshold by September, you will almost certainly cross $100,000 by year end. Registering and starting to collect in October, before crossing the threshold, avoids the gap between crossing the threshold and starting collection where you make taxable sales without collecting tax.

Reactive registration means waiting until you confirm you have crossed a threshold and then scrambling to register, configure collection, and begin filing. This approach creates a liability window between the trigger date and when you actually start collecting, where you made sales without collecting tax and owe the uncollected amount out of pocket. The window can be weeks to months depending on how quickly you discover the crossing and how long registration processing takes.

For sellers with clear growth trajectories, proactive registration in states where you are approaching the threshold is the financially prudent approach. The cost of registering and filing in a state where you will inevitably have nexus is small compared to the liability created by a multi-month gap of uncollected tax.

Steps to Start Collecting

Once you identify a state where you need to collect, follow these steps promptly. First, register for a sales tax permit through the state's department of revenue website or through the Streamlined Sales Tax Registration System for member states. Second, while waiting for permit processing (1 to 4 weeks in most states), configure your ecommerce platform's tax settings for the new state so you are ready to enable collection the moment your permit is approved. Third, once you receive your permit, enable collection on your store for that state. Fourth, set up filing reminders for the state's due dates and add the state to your compliance tracking system. Fifth, if there is a gap between your nexus trigger date and when you started collecting, evaluate whether a voluntary disclosure agreement is appropriate for the uncollected period.

Very Small Sellers: When Is It Worth the Effort

A seller doing $20,000 per year in total revenue is unlikely to cross economic nexus thresholds in any state other than their home state. The practical compliance obligation is limited to registering and collecting in your home state, which is manageable regardless of business size. As your revenue grows toward $100,000+, economic nexus triggers begin appearing in your highest-volume states, and the compliance investment becomes necessary.

If you sell exclusively on marketplaces (Amazon, Etsy, eBay) with no direct sales channel, the marketplaces handle tax collection and remittance on all orders. In this case, your only obligation may be registering in states that require it (which is a small number) and filing returns that show marketplace deductions. The practical tax work is minimal because the marketplace does the heavy lifting.

The point at which compliance becomes unavoidable is when you add a direct sales channel (your own website) and your combined sales across channels start crossing thresholds in multiple states. At that point, invest in a tax automation solution and set up proper compliance infrastructure. The cost of compliance is always lower than the cost of non-compliance discovered later.