Why U.S. Sales Tax is the most complicated consumption tax in the world

If you sell into the United States, you are dealing with one of the most fragmented consumption tax systems in the world.

This is not because sales tax is inherently complex.
It is because of how the system is structured.

The U.S. does not have a national sales tax. Instead, sales tax is administered at the state level, with additional layers imposed by counties, cities, and special taxing districts. Today, there are 46 separate state sales tax regimes and more than 12,000 unique taxing jurisdictions.

Each jurisdiction can independently determine:

• What is taxable

• What is exempt

• How tax is calculated

• When tax must be collected

• How and when returns must be filed

Rates are not the real problem. Rates are relatively easy to automate.

The real problem is lack of uniformity.

A product that is taxable in one state may be exempt in another. Shipping may be fully taxable, partially taxable, or exempt depending on the destination. Digital goods, SaaS, services, and bundled transactions are all treated differently across states, often with subtle distinctions that materially affect compliance. Sales tax exemption forms are handled differently across states.

There is also no centralized administration.

Businesses must register, file, remit, and respond to notices separately in every state where they are required to collect tax. Each state operates its own portal, uses its own forms and terminology, and enforces compliance differently.

Globally, this is unusual.

Most countries administer consumption taxes at the national level. Even when rates vary by region, the underlying rules are consistent. Businesses learn one system and apply it everywhere.

In the U.S., remote sellers must learn dozens.

This structural complexity existed long before e-commerce. But it became unavoidable after the 2018 Supreme Court decision that expanded states’ authority to require sales tax collection from out-of-state sellers.

If you want historical context on how we got here, I’ve written about that separately in A Brief History of U.S. Sales Tax. What matters today is this: the system small businesses are expected to comply with was never designed for modern interstate commerce.

Sales tax complexity is not about rates. It is about fragmentation, inconsistent rules, and decentralized enforcement.

Understanding this structural reality is the foundation for every sales tax decision that follows.

Wayfair’s unintended consequences: compliance challenges for small remote sellers

To mitigate the impact on small remote sellers, the federal Wayfair ruling required states to include a safe harbor provision in their sales tax laws. These provisions are meant to lessen the compliance burden by exempting businesses that fall below certain thresholds—typically based on sales volume or transaction count, like $100,000 in sales or 200 transactions—from the obligation to collect and remit sales tax.

While this was a step in the right direction, the varying safe harbor thresholds and requirements across states have created an overwhelming burden for small remote sellers. They must first determine where they have economic nexus based on the 46 different safe harbor provisions and then navigate the various requirements related to registration, return filings, notice responses, and audits.

Sales tax compliance in this environment is highly complicated, costly, and stressful for small remote sellers. Unlike large corporations with dedicated tax teams, these small businesses often lack the resources to confidently comply with the myriad state tax laws. Many small remote sellers who decide to pursue compliance turn to software solutions and external consultants, while others attempt to handle compliance in-house, often with less favorable outcomes.

Managing Sales Tax Compliance as a Small Business

If you’re a small remote seller, here are a few strategies to manage compliance more effectively:

1. Evaluate Software Solutions: Look for sales tax software that can automate calculation and reporting to ease (though not replace) the compliance process.

2. Consult an Expert: A sales tax consultant can help you understand nexus thresholds and manage filings across states, saving time and reducing the risk of errors.

Six years after the Wayfair ruling, challenges for small remote sellers persist. The ruling, while addressing inequities for local businesses, has inadvertently created barriers to small business creation, growth, and entrepreneurial spirit. Non-compliance—whether intentional or unintentional—poses a high risk, and many small sellers are increasingly anxious about potential audits in the coming years.