How Sales Tax Works in the US

Sales tax is one of the most misunderstood parts of the American financial system. Unlike income tax, it's invisible until the moment you pay — and unlike most countries' VAT systems, it varies wildly from one zip code to the next. This guide explains everything: what sales tax is, who sets the rates, who pays it, and how to calculate it correctly every time.

What Is Sales Tax?

Sales tax is a consumption tax levied by state and local governments on the sale of goods and, increasingly, services. When you buy a $50 shirt in Chicago, you pay more than $50 at the register — the extra amount is sales tax collected by the retailer on behalf of the government.

The key word is collected. Retailers don't keep sales tax — they act as intermediaries, gathering it from customers and remitting it to the appropriate tax authority. This means the legal obligation to remit the tax falls on the seller, not the buyer.

Sales Tax vs. VAT: What's the Difference?

Most countries use a Value Added Tax (VAT), where tax is applied at every stage of production and distribution. In the US, sales tax is only applied at the final point of sale to the end consumer. This makes the US system simpler for consumers to understand, but more complex for businesses to administer — since rates vary by jurisdiction, not by product stage.

Who Sets Sales Tax Rates?

The United States has no federal sales tax. Instead, the authority to levy sales tax rests entirely with state and local governments — which is why American sales tax is so complicated compared to the rest of the world.

There are three layers of sales tax in the US:

The 5 States With No Sales Tax

Five US states have chosen not to implement a statewide sales tax:

Highest & Lowest Combined Rates

When you factor in average local rates, the difference between the highest and lowest-taxing states is dramatic:

See full rates for all 50 states in our Sales Tax Rates by State reference table →

How to Calculate Sales Tax

The math is straightforward once you know the correct combined rate for your location:

Working Backwards: Tax-Inclusive Prices

Sometimes you know the final price and need to find the pre-tax subtotal. This is common when splitting expenses or verifying a receipt:

Sales Tax Nexus: When Businesses Must Collect

Not every business is required to collect sales tax in every state. The concept of nexus determines when a business has enough of a connection to a state to be legally obligated to collect and remit that state's sales tax.

Physical Nexus

If your business has a physical presence in a state — an office, warehouse, employees, or even a temporary pop-up shop — you have physical nexus there and must collect sales tax from customers in that state.

Economic Nexus (Post-2018)

The landmark 2018 Supreme Court ruling in South Dakota v. Wayfair changed everything. States can now require out-of-state sellers to collect sales tax if they exceed a certain threshold of sales into that state — typically $100,000 in sales or 200 transactions per year. This primarily affects e-commerce businesses that sell nationally.

What's Exempt From Sales Tax?

Not everything is taxable. Most states carve out exemptions for certain categories — though the rules vary enormously by state:

Origin vs. Destination Sourcing

For in-person sales, the tax rate is simple: wherever the store is located. For online and remote sales, it gets more complex — states use one of two systems to determine which rate applies.

Destination-Based Sourcing (Most States)

The tax rate of the buyer's address applies. If you're an Arizona seller shipping to a customer in New York, you collect New York's tax rate. This is the more common approach and now required by most states with economic nexus laws.

Origin-Based Sourcing (Fewer States)

The tax rate of the seller's location applies. A handful of states — including Texas, Arizona (for in-state sales), and a few others — use origin-based sourcing for intrastate transactions. This simplifies compliance for sellers but can confuse buyers.

Sales Tax for Small Businesses: A Practical Checklist

If you run a small business and sell physical products, here's what you need to do to stay compliant:

Tips for Consumers

As a shopper, sales tax affects your budget every day. Here's how to think about it:

Always Calculate the True Cost

When budgeting for a purchase, remember to add the combined sales tax rate. A $500 laptop in Tennessee will actually cost you around $548 at the register. Use our calculator to find the true price before you commit.

Online Shopping and Use Tax

Even when online retailers don't charge sales tax at checkout, you may legally owe use tax — the consumer-side equivalent. Most states technically require residents to self-report and pay use tax on untaxed online purchases, though enforcement for individual consumers is rare.

Cross-Border Shopping

If you live near a state border, it may be worth comparing prices inclusive of tax. Shopping in a no-tax or low-tax state can generate meaningful savings on large purchases like electronics, furniture, or appliances.

A Brief History of US Sales Tax

Sales tax is relatively modern by American standards. Mississippi became the first state to adopt a general sales tax in 1930 during the Great Depression, as states scrambled for revenue. By 1970, all but five states had followed suit.

The internet era fundamentally disrupted the system. For decades, online retailers like Amazon could legally avoid collecting sales tax in states where they had no physical presence — under a rule established by the 1992 Supreme Court case Quill Corp. v. North Dakota. This gave e-commerce a significant pricing advantage over brick-and-mortar stores.

That changed in 2018. The Supreme Court's decision in South Dakota v. Wayfair overturned Quill and allowed states to require economic nexus — meaning online sellers crossing revenue thresholds now had to collect tax just like physical stores. Within two years, every state with a sales tax had passed economic nexus legislation.