You buy a $4,000 laptop for your business from an out-of-state seller. The checkout page charges $0.00 in sales tax. Nice deal — except it isn't. In nearly every state with a sales tax, you now owe that same tax directly to your own state government. It even has its own name: use tax. And unlike the tax the seller collects for you, nobody will remind you to pay this one until an auditor does.
This is one of the most commonly missed obligations in small business tax. Not because owners are careless, but because the system is backwards from everything else: the buyer, not the seller, is on the hook. Here's how use tax works, when it hits you, and how to handle it without drama.
What Use Tax Actually Is
Use tax is the mirror image of sales tax. Sales tax applies when a seller in your state sells you something taxable. Use tax applies when you store, use, or consume something taxable in your state and no sales tax was collected on the purchase.
The two taxes are complementary by design:
- If the seller charged you sales tax, you owe no use tax on that purchase.
- If the seller charged nothing — or charged too little — you owe the difference to your state.
The tax rate is generally the same rate that would have applied at your location: your state rate plus any applicable county and city add-ons, based on where you use the item rather than where you bought it. The purpose is twofold: it protects local merchants, who must collect tax, from being undercut by out-of-state sellers who don't, and it keeps the state's revenue whole as commerce moves online.
One point of confusion worth clearing up early: use tax is not a second tax on top of sales tax. You never pay both on the same purchase. It is the same tax, collected from a different person because the normal collection point never fired.
When Small Businesses Owe It: The Five Common Triggers
Most use tax bills trace back to one of a handful of everyday situations. Walk through each and ask whether it describes something your business did this year.
1. Online and out-of-state purchases with no tax charged
This is the big one. You order equipment, supplies, furniture, or software from a seller that has no obligation to collect tax in your state, and the invoice arrives with no tax line. The obligation to pay didn't disappear — it moved to you.
Marketplace facilitator laws have shrunk this category since large platforms now collect in most states, but it is far from gone. Small vendors, foreign sellers, and sellers below a state's collection threshold still ship tax-free every day. Every one of those invoices is a potential use tax liability sitting in your inbox.
2. Inventory you pull out for business use
Buy goods for resale under a resale certificate, and no tax is charged — correctly. But the moment you take an item off the shelf and use it yourself, the deal changes. The office computer grabbed from store stock, the sample given to an employee, the display unit retired to the break room: each is a taxable use, and you owe use tax on your cost of the item.
Auditors check this routinely because businesses almost never track it. If you ever withdraw inventory for internal use, you need a process that flags it at the time — reconstructing it two years later during an audit is painful and expensive.
3. Purchases where the seller charged the wrong amount
Use tax also covers the shortfall when a seller under-collects. Common versions: an out-of-state vendor collects its own state's 4% rate instead of your 8.5% combined rate, or a vendor treats a taxable item as exempt. You owe the difference.
Keep the invoice. States generally give you a credit for sales tax legally owed and paid to another state on the same purchase, so you pay only the gap — but you have to document what you already paid to claim it.
4. Taxable property you bring into the state
Move equipment, vehicles, or other business property across state lines and your new state may want use tax on it. The classic case is buying a vehicle or boat out of state and registering it at home, where the tax is collected at registration. But the same principle reaches business assets relocated to a new office or job site, depending on the state's rules and how long the property was used elsewhere first.
5. Digital goods and software, depending on your state
Taxability of electronically delivered software, cloud subscriptions, and digital products varies enormously by state — taxable in some, exempt in others, and taxable-only-if-customized in a few. When a vendor doesn't collect because it assumes its product is exempt everywhere, buyers in taxing states inherit the liability. If your business spends meaningfully on software from vendors that never charge tax, verify your state's position rather than assuming the vendor got it right.
How to Pay It: Self-Accrual in Practice
Nobody sends you a use tax bill. You calculate it and remit it yourself — a process states call self-assessment or self-accrual. The mechanics depend on whether your business already files sales tax returns.
If you already hold a sales or seller's permit
This is the easy path. Nearly every state's sales tax return includes a line for reporting taxable purchases on which no tax was paid — often labeled "purchases subject to use tax." Each filing period, you:
- Review vendor invoices for taxable purchases where no tax (or too little tax) was charged.
- Total the purchase prices of those items.
- Enter the total on the use tax line of the return you already file, and pay the computed tax with it.
No separate registration, no separate form. The return you already file is the vehicle; the only new habit is the invoice review.
If you don't file sales tax returns
Service businesses, wholesalers, and others with no selling activity still owe use tax on their purchases. States handle this in a few ways:
- A standalone consumer use tax return, filed annually or periodically through the state's tax portal. Several states let businesses register for a use-tax-only account for exactly this purpose.
- A use tax line on the state income tax return, common for individuals and sometimes available to pass-through owners for smaller amounts.
- Registration thresholds that force the issue. A few states require businesses above a certain purchase volume to register for use tax collection even if they make no sales at all.
Check your state revenue department's guidance for the exact form and frequency. The key insight is that "we don't sell anything taxable" is not an exemption from use tax — it just changes which form you file.
Claiming credit for tax already paid
When you paid some tax to another jurisdiction on the same item, most states credit it against the use tax due, so you owe only the difference between the two rates. If you paid 4% to the seller's state and your combined rate is 8.5%, you remit 4.5%. If you paid more than your home rate, you generally owe nothing further — though you don't get a refund of the excess either. Keep every invoice showing tax paid; without it, the auditor will assume you paid zero.
Why Auditors Love Use Tax
Ask a state auditor where the easy money is, and use tax tops the list. The reasons are structural, and understanding them is the best motivation to self-assess before you're asked to.
Almost nobody volunteers it. Compliance rates on buyer-remitted use tax are notoriously low, especially among businesses that don't file sales tax returns. An auditor who opens your books knows before starting that there is very likely an assessment waiting. Low-hanging fruit gets picked first.
Your own records prove the case. Auditors don't need to catch you doing anything. They sample your accounts payable, fixed-asset additions, and expense accounts, pull the invoices, and check whether tax was charged. Every untaxed invoice for a taxable item becomes tax due plus interest plus penalties. The workpapers practically write themselves.
Fixed assets are a goldmine. A single untaxed equipment purchase — manufacturing machinery, servers, vehicles, construction materials — can produce a five-figure assessment on its own. Auditors routinely start with the fixed-asset ledger for exactly this reason. If your business capitalized any big out-of-state purchase this year, assume an auditor would find it.
Failure to file extends the auditor's reach. In many states, the statute of limitations doesn't run on periods for which no return was filed. A business that never filed a use tax return can face a lookback far longer than the standard three or four years. Filing and paying something — even imperfectly — starts the clock.
Penalties stack on top. Beyond the tax itself, expect interest running from the original due date plus penalties for failure to file, failure to pay, or negligence. Voluntary disclosure programs in most states will waive or reduce penalties if you come forward before you're contacted — another reason to fix this on your schedule rather than the auditor's.
None of this requires intent to evade. "I didn't know" reduces penalties in some states but never eliminates the underlying tax. The obligation exists whether or not you knew about it.
A Simple Monthly Habit That Keeps You Clean
Full-time use tax software is overkill for most small businesses. What you need is a lightweight monthly routine, built into the bookkeeping you already do:
- Flag untaxed invoices at entry. When recording a vendor bill, note whether sales tax was charged. A simple tag or custom field — "tax paid" vs. "no tax charged" — turns a year-end scavenger hunt into a filtered report.
- Review the untaxed list monthly. For each flagged purchase, ask: was this item taxable in my state? If yes, accrue the use tax in your books that month so the liability is visible, not a surprise.
- Track inventory withdrawals. Log every item pulled from resale inventory for business use, with its cost. One line per item, recorded when it happens.
- Keep invoices for everything. Digital copies are fine. You need them both to compute what you owe and to prove credits for tax paid elsewhere.
- Reconcile before each filing. The accrued use tax balance in your books should tie to what you report on the return. If it doesn't, find out why before you file.
Proper bookkeeping is genuinely the whole game here. Use tax compliance fails in businesses whose purchase records can't answer a simple question — "which invoices had no tax?" — and succeeds in businesses whose books answer it in one report. Tracking purchases with tax-paid flags takes seconds per invoice and converts an audit nightmare into a routine filing. If you want to see how your purchase data flows through to reports, the Fava dashboard gives you a visual view of every account, and the docs walk through setting up custom tracking for exactly this kind of workflow.
Keep Your Purchase Records Audit-Ready
Use tax feels unfair the first time you hear about it — a tax nobody told you about, on purchases where the seller stayed silent. But once you see it for what it is — the same sales tax, routed through you instead of the cash register — compliance becomes a bookkeeping habit rather than a gamble. Flag untaxed invoices, accrue monthly, and file what you owe.
Maintaining clear purchase records is what makes all of this painless instead of painful. Beancount.io provides plain-text accounting that gives you complete transparency and control over your financial data — no black boxes, no vendor lock-in. Get started for free and see why developers and finance professionals are switching to plain-text accounting.
