Sales Tax for Small Businesses: What You Need to Know

Sales tax is money you collect for the government, not revenue you earn, and the rules about when to collect it have changed dramatically since 2018. This explainer covers how sales tax works, when a small business has to register, what is taxable and how to set up collection and filing without losing sleep.

Woman in a rust-colored sweater paying with a card at a salon counter — Every taxable sale adds a small amount the business holds in trust until the next filing.

Key takeaways

Sales tax is charged to the customer at the point of sale and passed to the state. It is never the business's money.
You must collect in any state where you have nexus, which can be created by physical presence or by crossing an economic threshold through sales alone.
Whether a product or service is taxable depends on the state, and the rate depends on the exact delivery address.
Most other countries use VAT or GST instead, with registration thresholds and credits for tax paid on purchases.

Few topics confuse new owners more than sales tax, and for good reason. In the United States there is no national sales tax. Instead, 45 states plus Washington, DC, charge a statewide sales tax, and thousands of counties, cities and special districts add their own. By the Tax Foundation's count there are well over 10,000 separate sales tax jurisdictions in the country, each with its own rate and sometimes its own rules on what is taxable.

The five states without a statewide sales tax are Alaska, Delaware, Montana, New Hampshire and Oregon, though some Alaska localities charge their own. If you sell only in one of those states and only to local customers, you may escape sales tax entirely. Everyone else needs a plan.

How sales tax actually works

The mechanics are simple. When you make a taxable sale, you add the correct rate to the price, collect the total from the customer, and record the tax portion separately. On a schedule set by the state, monthly, quarterly or annually depending on your volume, you file a return listing taxable sales and remit the tax collected. Some states let you keep a tiny discount for filing on time.

The key mental shift is this: sales tax collected is a liability, not income. It should sit in a separate account or at least a separate line in your books from the day you collect it until the day you remit it. Businesses that treat it as working capital are the ones that end up with a bill they cannot pay.

Common mistake

Assuming that because you are a small business, or an online business, sales tax does not apply. Since 2018, a business with no physical presence in a state can still be required to collect tax there once its sales to that state cross a threshold. Marketplace platforms often handle this for you, but your own website does not.

Nexus: where you are required to collect

Nexus is the legal connection between your business and a state that gives the state the right to require you to collect its tax. There are two main kinds.

Physical nexus

You have physical nexus in a state where you have an office, store, warehouse, employee, inventory (including inventory held in a third-party fulfillment center) or where you regularly attend trade shows and make sales. Your home state is almost always one.

Economic nexus

In the 2018 case South Dakota v. Wayfair, the US Supreme Court ruled that states can require out-of-state sellers to collect sales tax based on economic activity alone. South Dakota's law set the bar at $100,000 in sales or 200 transactions into the state per year, and most states adopted similar thresholds. Many have since dropped the transaction count and rely on a dollar threshold, commonly $100,000, though a few states use higher amounts and the details change, so check each state where you sell.

$100,000 The annual sales threshold into a single state that most US states use to create economic nexus for remote sellers, following the 2018 Wayfair decision Thresholds vary by state and are revised periodically

Marketplace facilitator laws

If you sell through a large marketplace such as Amazon, Etsy or eBay, the platform is generally required to collect and remit sales tax on your behalf in nearly every state. That removes most of the burden for marketplace sales, but it does not cover sales from your own website, invoices or in-person events. Those remain your responsibility, and marketplace sales usually still count toward your economic nexus thresholds.

What is taxable

As a general rule in the US, tangible goods are taxable unless exempted, and services are exempt unless specifically taxed. But the exceptions are wide. Groceries, prescription medicines and clothing are exempt or reduced in some states and fully taxable in others. Digital products such as software downloads, ebooks and streaming are taxable in a growing number of states. Some states tax specific services like repairs, landscaping or data processing.

Software as a service is the clearest example of the mess: depending on the state it may be fully taxable, partly taxable or exempt. If you sell anything digital across state lines, you need a product taxability map or a tax engine that maintains one.

Category	Typical US treatment	Watch out for
Physical goods	Taxable in most states	Exemptions for food, medicine, clothing in some states
Services	Exempt in most states	States that tax specific services; bundled goods and services
Digital products and SaaS	Varies widely	Rules change often; check each state's definition
Shipping charges	Varies	Taxable in some states when the item is taxable
Sales for resale	Exempt with a valid certificate	Keep the certificate on file or you owe the tax

Exemption certificates

Wholesale customers, nonprofits and some government bodies can buy without paying sales tax if they give you a valid exemption or resale certificate. The burden is on you to collect and keep the certificate. If an auditor finds an untaxed sale with no certificate, you owe the tax, plus penalties, out of your own pocket.

Origin versus destination sourcing

Which rate applies? Most states are destination-based: the rate at the customer's delivery address applies. A handful are origin-based for in-state sales, meaning the rate at your location applies. For remote sellers shipping into a state, destination rates almost always apply. This is why two customers in the same state can pay different rates, and why manually looking up rates for every order becomes impossible beyond a trickle of sales.

Person using a point-of-sale terminal at a store counter — Modern point-of-sale and ecommerce systems can calculate the right rate automatically, if you set them up correctly.

How to set up sales tax compliance, step by step

List every state where you have physical presence. Home office, storage, employees, contractors who work regularly for you, inventory in fulfillment centers.
Run a nexus check on your sales by state. Pull the last twelve months of sales grouped by shipping state and compare each total to that state's economic threshold. Repeat quarterly as you grow.
Register before you collect. Apply for a sales tax permit in each state where you have nexus. Collecting tax without a permit is illegal in most states. Registration is usually free or low-cost and done online.
Determine taxability of your products in each state. Use the state's guidance or a tax engine's product codes. When unsure, ask the state's taxpayer help line; they are usually helpful and the answer is free.
Configure your sales channels. Turn on tax collection in your ecommerce platform, point-of-sale system and invoicing tool for each registered state, with the correct product categories.
Separate the money. Move collected tax into a separate bank account weekly, or at minimum track it as a liability.
File and remit on schedule. Each state assigns a filing frequency. File even when you collected nothing; a "zero return" is still required and skipping it triggers penalties.
Keep records for at least four years. Sales by jurisdiction, exemption certificates and filed returns. Statutes of limitation vary by state.

Worked example

Suppose a small candle maker in Texas sells through her own website. In the past twelve months she shipped $140,000 of orders to California, $60,000 to Florida and smaller amounts to thirty other states. She has physical nexus in Texas and economic nexus in California, where she crossed the $100,000 threshold. Florida and the other states are below threshold, so she does not need to register there yet. She registers in California, enables destination-based tax calculation for California orders in her store, and sets a quarterly reminder to re-run the check. If Florida sales keep growing, she registers there once she crosses its threshold.

Pro tip

If you discover you should have been collecting in a state for a while, do not simply start now and hope. Many states offer voluntary disclosure programs that limit the look-back period and waive penalties if you come forward before they find you. Talk to a sales tax specialist first.

Tools and automation

For a single-state business with simple products, your point-of-sale or ecommerce platform's built-in tax settings are usually enough. Once you are registered in several states or sell digital goods, a dedicated sales tax engine that calculates rates by address, tracks nexus thresholds and files returns becomes worth its subscription fee. Compare the cost of the tool with the cost of an hour of your time per state per filing period, and the decision is usually easy.

Automate when

You are registered in three or more states
You sell digital products or SaaS across state lines
You handle many exemption certificates

Keep it manual when

You sell in one state with a single rate
Nearly all your sales go through a marketplace that collects for you
Your volume is low enough to file once a year

Outside the United States: VAT and GST

Most countries do not use a US-style sales tax. They use value-added tax (VAT) or goods and services tax (GST), which is charged at every stage of the supply chain. The main differences for a small business:

Registration thresholds. You usually do not have to register until turnover passes a threshold. In the UK it has been £90,000 of taxable turnover; in Australia, A$75,000; in Canada, the federal "small supplier" limit is C$30,000. These figures change, so check the current numbers.
Input tax credits. Once registered, you reclaim the VAT or GST you paid on business purchases, so the tax falls on the end consumer rather than on you. This is why voluntary registration below the threshold can make sense for businesses with large purchases.
Prices often include tax. In many countries consumer prices must be displayed including VAT, unlike the US habit of adding tax at the register.
Cross-border digital sales. The EU and many other jurisdictions require foreign sellers of digital services to register and charge local VAT from the first sale, with simplified schemes for reporting.

Rates, thresholds and rules are set nationally and change with each budget, so always confirm the current position with your tax authority or an accountant in your country.

Sales tax setup checklist

List all states or countries where you have physical presence
Run a sales-by-state nexus check against current thresholds
Register for a permit in each state where you have nexus
Map product taxability for each registered state
Enable tax collection in every sales channel
Open a separate account or liability tracking for collected tax
Calendar every filing deadline and file zero returns when needed
Collect and store exemption certificates from every tax-exempt buyer

Frequently asked questions

Do I charge sales tax to customers in other countries?

US sales tax applies to deliveries within the taxing state, so exports are generally not subject to US sales tax. However, the destination country may require you to register for its VAT or GST, especially for digital goods, so check the rules where your customers are.

What happens if I collected tax but did not remit it?

This is treated seriously because the money belongs to the state. Penalties and interest accrue, and in many states the owner can be held personally liable regardless of the business's legal structure. File and pay as soon as possible and contact the state if you need a payment plan.

Is sales tax deductible as a business expense?

Sales tax you collect from customers is neither income nor an expense; it passes through. Sales tax you pay on your own business purchases is part of the cost of those items and is deductible along with them.

How often do I need to file?

The state assigns a frequency when you register, typically monthly for larger collectors, quarterly for mid-size and annually for very small amounts. The state may change your frequency as your volume changes, so watch for notices.

The bottom line

Sales tax is manageable if you treat it as a system: know where you have nexus, register before you collect, charge the right rate for each delivery address, keep the money separate and file on time. Marketplaces and tax engines now handle much of the mechanical work, but the responsibility stays with you. Thresholds, rates and taxability rules change constantly and differ by state and country, so check current guidance before relying on any figure in this article.