Somewhere in your bank account right now there may be money that was never yours. It arrived looking like every other payment, sitting in the same balance as your rent and your groceries. You will not feel the difference until a letter from a state revenue department arrives, asking for a tax you never knew you were supposed to collect, for sales you made a year or two ago.

Most freelancers never meet this problem. Some meet it hard. The difference comes down to one question that almost nobody asks before sending their first invoice: what exactly did you sell?

Two taxes that people keep confusing

The taxes freelancers worry about are almost all taxes on you: income tax, self-employment tax, the quarterly estimated payments. Sales tax is a different animal. It is a tax on the buyer, and you are only the collector. When it applies, you add it to the invoice, hold it, and send it to the state. It is not your income, and it is not your expense.

That last point catches people. Sales tax you collect is not revenue on your Schedule C in the way your fee is. It is closer to money you're holding in trust. If you spend it, you haven't earned an extra bonus. You've borrowed from the state, and the state will want it back, often with penalties and interest.

The first test: is it a product or a service?

Historically, U.S. sales tax was built around tangible goods: things you could pick up. Services were largely left out. So in many states, a freelance writer, consultant, designer, or coach charges no sales tax on their time and expertise, because the state simply doesn't tax that category.

But "most states don't tax services" is not the same as "no state taxes services." The map is uneven:

  • A few states tax services broadly. Hawaii's general excise tax and New Mexico's gross receipts tax are both levied on the business doing the selling, and both reach a wide range of services.
  • Many states tax a specific list of services, such as certain repair, installation, or data-related work. Texas, for example, taxes some categories of services that other states ignore.
  • Most states tax tangible goods, and a growing number extend that to digital products or software. Whether a downloadable template pack, a stock photo license, or a software subscription counts depends on the state's wording.

That last category is where modern freelancers get caught. If you only sell your hours, you're probably in the safe zone in most places. If you sell something you can download, install, or log into, you are closer to the line, and the line moves by state.

The second test: does the state have a claim on you at all?

For decades the rule for collecting out-of-state sales tax was physical presence. If you had no office, employees, or inventory in a state, that state generally couldn't make you collect from its residents.

That changed in 2018, when the Supreme Court decided South Dakota v. Wayfair. The Court allowed states to require out-of-state sellers to collect tax once they had enough economic activity there, even with no physical footprint. This is called economic nexus.

Many states adopted thresholds based on sales volume into the state, commonly something like $100,000 in annual sales, and some also counted a number of transactions. The details differ and have been revised over time, so you should check the current rule for any state where you sell a lot. The principle is what matters: a freelancer working from a spare bedroom in one state can cross into another state's tax net purely by selling to its residents.

Notice what this means for the service-vs-product test. If you sell only services, and the buyer's state doesn't tax those services, nexus is irrelevant. Nexus only bites when the thing you sold is taxable where the customer is.

Who is actually responsible when you sell through a platform

If you sell through a large marketplace, the picture simplifies. Most states now have marketplace facilitator laws, which put the collection duty on the platform, not the individual seller. Etsy, Amazon, and similar marketplaces generally collect and remit on your behalf for sales made through them.

The catch is that this covers the platform's sales. A direct invoice to a client, a product sold from your own site, or a course on your own storefront is yours to figure out. Freelancers who run a mix, say marketplace sales plus direct client work, often assume the platform's handling covers everything. It doesn't.

Why the penalty feels so unfair

There's a reason this one hurts emotionally in a way income tax doesn't. When you owe income tax, you at least earned the income. When a state assesses back sales tax, you are being asked to pay a tax you could have charged your customer, but now cannot, because the invoice is closed and the relationship may be over. You eat the full amount out of your own pocket.

That asymmetry is the real lesson. Sales tax is cheap to handle prospectively, since you add a line to an invoice. It is expensive to handle retroactively, since you pay it from profit. The cost of not knowing grows silently with every sale.

Your next moves

You don't need an accountant to find out where you stand. Here is a way to settle it this week:

  • List what you actually sell. Write one line per offer: hourly consulting, a fixed-fee project, a downloadable file, a template, a software or membership access. Mark each one as service, digital product, or physical product.
  • Look up your own state's rules for each line. Search "[your state] sales tax on [that type of service or digital product]" and read the state revenue department's page, not a blog summary. Write down yes, no, or unclear.
  • Pull your last twelve months of sales by customer state. Export from your invoicing tool, Stripe, or your bank deposits. Sort by state and note any where you sold a taxable item and the total is large.
  • Check those states' economic nexus thresholds. For any state where you sold a taxable product, look up the revenue and transaction thresholds on that state's revenue department site, and see how close you are.
  • If something is taxable and you've crossed a threshold, register before you collect. Don't add tax to invoices until you hold a sales tax permit, then set up a separate savings bucket for the collected tax so it never mixes with your own money. If you're unsure, a short consult with a CPA is cheap next to an assessment.

The pattern behind the surprise

It is easy to read all this as a sign that freelancing is a minefield. It isn't. For most people who sell only their time, the answer will be a quick no, and the whole exercise takes an hour. What the exercise buys you is certainty instead of a low background dread, the feeling of a bill that might exist.

That dread is worth taking seriously, because it is how people end up avoiding their tax picture entirely. The fix is the same for every tax you owe: know the rule, know the number, know the date, before the date knows you.

That is the habit Payday was built around. It connects to Stripe or your bank, works out your Q1 through Q4 estimated payments, nudges you ahead of each deadline, and exports a TurboTax-ready file, so the income-tax side of your year stops being a guess. Sales tax is its own check, but once the quarterly math is handled, you have the headroom to ask these questions calmly. If that sounds useful, you can take a look at Payday.