Sales tax is the part of running a store that looks simple until the first notice arrives. It is not one tax. In the United States it varies by state, county and city, with different rules on what is taxable, and in other markets value added tax, goods and services tax and customs duties each have their own rules. For a store that sells across borders, the question is no longer whether to deal with tax but how to do it without spending every month on it.
Automation helps a great deal, but only for the parts that can be automated. This article separates those clearly: what software can do, what it cannot, what to track, and how to connect tax to the rest of your finance routine. It is general information for store owners, not tax advice; rules differ by place and change, so confirm the specifics with a qualified adviser. If you also want the bookkeeping side, read the monthly bookkeeping checklist and the Shopify and QuickBooks guide.
The five questions of sales tax
| Question | What it means | Who decides |
|---|---|---|
| Where do I have an obligation? | Physical presence, or sales above a threshold, can create nexus; rules differ by place | You, with advice |
| Do I need to register there? | Registration is usually required before collecting | You, with advice |
| What is taxable? | Products and services are treated differently by location | Rules plus advice; software encodes the result |
| What rate applies? | Depends on the destination, sometimes the origin, and on product type | Software |
| When and how do I file and pay? | Schedules and portals differ | Software prepares; you or an agent files |
Only the fourth question and the preparation half of the fifth are really mechanical. The first three depend on facts about your business and on rules you must interpret. Most mistakes come from treating the whole thing as a software problem.
Nexus and thresholds in plain words
Nexus is the connection that makes a seller responsible for collecting tax in a place. Physical presence, such as a warehouse, an employee or inventory stored there, has long created nexus. In the United States, economic nexus rules mean that sales above a threshold into a state can create an obligation even without any physical presence. Thresholds, how they are measured and which sales count differ between states and have changed over time. Other regions have their own distance-selling and registration thresholds.
What this means for you is practical: keep a running total of sales by state or country, measured the way each place measures it, and set an alert at a safe distance below each threshold so you can decide before you pass it, not after. Marketplaces may collect and remit tax for some sales on your behalf, which can change what counts toward your own thresholds, so ask your adviser how to treat them.
What tax software does
- Calculates at checkout. Looks up the rate for the destination address and product category and adds the right amount.
- Records the detail per order. Stores the jurisdiction, rate, taxable amount and tax, which you need for returns and audits.
- Monitors thresholds. Shows sales by place against registration thresholds and warns as you approach them.
- Handles exemptions. Stores certificates for resellers or exempt customers where applicable.
- Adjusts for refunds. Reverses the tax with the refund.
- Prepares returns. Totals by period and jurisdiction, and in some cases files for you.
- Keeps rates current. Rates change; the software updates them.
What software does not decide
- Whether you have nexus. Software can show your numbers; the legal conclusion is yours.
- Whether to register. Registration has costs and obligations, and the timing can matter.
- Product taxability when it is unclear. Clothing, food, digital goods, bundles and shipping charges are treated differently in different places.
- Exemption eligibility. Software stores certificates; it does not judge their validity.
- Past exposure. If you have collected too little in the past, an adviser can help you decide how to deal with it.
Set it up in a sensible order
- Map your footprint. List where you store inventory, where staff work and where you sell.
- Pull your sales by destination for the last twelve months and compare against thresholds.
- Take advice on registration where you are over or close to a threshold.
- Register where required, and note filing schedules and portal logins.
- Configure tax in your store platform and a tax calculation service if needed.
- Assign tax categories to products where treatment differs.
- Connect the numbers to your books so that tax collected posts to a liability account.
- Set a monthly review to reconcile and check thresholds.
Product tax categories
Many stores sell items that are taxed differently: clothing may be exempt in one place and taxable in another, food and drink vary, digital products have their own rules, and shipping is sometimes taxable. Tax software uses product tax codes to apply the right treatment. The task is to assign a code to each product and keep it up to date. This is where catalogue data and tax meet: a product with no category falls to a default, which may be wrong. Our product data enrichment work can propose categories from titles and attributes, with a person confirming the result.
| Product type | Typical issue | What to do |
|---|---|---|
| Clothing | Treatment varies by place and price | Assign the correct code; review with advice |
| Food and drink | Different rules for groceries and prepared items | Separate categories |
| Digital goods | Separate regimes in many places | Use a digital category; check each market |
| Bundles | Mixed taxability inside one price | Decide how to split or treat the bundle |
| Shipping and handling | Sometimes taxable, sometimes not | Configure per jurisdiction |
Reconcile every month
Reconciliation is where automation pays for itself. Compare the tax your store collected with the tax your software calculated and with the liability in your books. Differences point to rounding, refunds, products with the wrong code, orders created outside the checkout, such as manual or marketplace orders, or taxes included in prices. Investigate each difference above a threshold you choose. Our payout reconciliation guide uses the same method for money, and the payout reconciliation and bookkeeping service can include tax lines.
| Check | Why |
|---|---|
| Tax collected by place against liability account | Confirms the books match the platform |
| Refund tax reversals | Prevents overpaying |
| Orders with zero tax in taxable places | Finds missing codes or exemptions |
| Marketplace orders | Confirms who collected the tax |
| Sales against thresholds | Warns before a new obligation begins |
International sales
Selling abroad adds more regimes: value added tax or goods and services tax in many countries, import duties and low-value consignment rules. Some regions let sellers use a single registration to report sales across several countries; others require registration country by country. Customers sometimes expect prices that include duties and tax, while others accept paying on delivery. Rules and thresholds change, so use the official guidance for each market and an adviser who knows it. Automation can display tax-inclusive prices, calculate duties where the software supports it and record everything for filing.
Marketplaces
Many marketplaces calculate, collect and remit tax on behalf of sellers in some places, though the details differ by marketplace and region. Your own website orders remain your responsibility. When you sell both, keep the two flows separate in your records and know which sales count toward which obligation. Your adviser can tell you how to treat marketplace-facilitated sales when assessing thresholds.
A worked example
A store sells $360,000 a year, spread across many US states. Its monthly report shows that sales to one state have reached about $82,000 in the last twelve months, close to the threshold that state uses. Because the store set an alert at 80 percent of each threshold, it sees this four months before it would cross the line, takes advice, registers in time and starts collecting from the first day it is required. Without the alert, the store would have discovered the obligation after crossing it and faced back-tax on sales where it had not collected. The numbers are illustrative; the pattern, a continuous measurement with an early warning, is the point.
Where Checkout Loom fits
We do not give tax advice or file returns. We connect the pieces around them: a clean flow of order and tax data into your books, product categories that the tax tool can use, threshold monitoring from your order history, monthly reconciliation reports and exception alerts. See finance, risk and reporting and sales reporting.
Mistakes to avoid
- Assuming a marketplace handles everything, including your own site’s sales.
- Waiting for a notice before checking thresholds.
- Leaving products uncategorised so the default applies.
- Not reconciling, so that errors accumulate for months.
- Treating software as an adviser. It calculates; it does not interpret the law.
- Ignoring refunds, which reduce the tax owed.
Sources and further reading
Figures and rules in this guide come from the primary pages below. Platform limits and prices change, so open the page before you build on a number.
- Streamlined Sales Tax Governing Board, information on multistate sales tax simplification
- South Dakota v. Wayfair, 585 U.S. (2018), Supreme Court, the decision that allowed economic nexus rules
- European Commission: VAT e-commerce rules, overview of EU VAT rules for online sales