How software is taxed comes down to four questions: what kind of software it is, how it reaches the buyer, where the buyer uses it, and whether the seller has enough of a footprint in the buyer’s state to be required to collect tax there. Get any of those wrong and you either overcharge customers or face back-tax assessments with interest and penalties layered on top. There is no single national rule, and the answers differ meaningfully from one state to the next.
Prewritten Software Is Almost Always Taxable
The most important distinction in software taxation is between prewritten (sometimes called “canned”) software and custom software. Prewritten software is anything built for general use and sold to multiple customers without significant modification: operating systems, office suites, accounting packages, off-the-shelf design tools. Nearly every state with a sales tax treats these as taxable, because they function like any other mass-market product.
Custom software is different. When a business hires a developer to build an application tailored to its specific operations, most states treat that transaction as a purchase of professional services rather than a product. The buyer is paying for expertise and labor, not acquiring a pre-existing item, so the development fees are typically exempt.
The gray zone is where a seller takes a prewritten product and modifies it heavily for one customer. Whether that hybrid gets taxed as canned software or qualifies as a custom service depends on how much modification occurred and, critically, how the invoice is structured. Separating the base license charge from the custom development charge on the invoice is the single most important step for supporting the custom classification in an audit. Lump everything into one line item and auditors will generally default to treating the whole amount as taxable prewritten software.
Delivery Method Changes the Answer
How the software reaches the buyer matters as much as what it is. States sort software into tangible personal property and intangible property, and the same program can land in different buckets depending on delivery.
Software shipped on a physical medium like a USB drive or disc is taxed like any other retail purchase in virtually every state with a sales tax. Digital downloads are less consistent. Some states have updated their tax codes to explicitly include electronically delivered software in their definition of taxable property. Others have not, meaning a download of the exact same program that would be taxed on a disc might escape taxation entirely when delivered over the internet. A state that taxes “tangible personal property” without mentioning digital goods may exempt downloaded software by default; a neighboring state that defines taxable property to include “digital products” or “specified digital goods” will tax the same transaction.
SaaS and Cloud Subscriptions
Software as a Service creates a genuinely difficult classification problem. The customer never downloads or owns a copy. They log in through a browser or app, use the provider’s software on the provider’s servers, and pay a recurring subscription fee for access. Is that a product, a rental, or a service?
States have answered differently. Some treat SaaS as a taxable sale of prewritten software, reasoning that the customer is still using a canned application regardless of where it’s hosted. Others classify it as a taxable data processing or information service, applying existing service tax rules. A meaningful number of states exempt SaaS entirely, viewing it as a non-taxable service because no transfer of software ownership occurs. The picture keeps shifting as states update their rules to capture revenue from a delivery model that barely existed when most sales tax codes were written.
For SaaS providers, this means tracking the tax treatment in every state where they have customers and nexus. Misclassifying a subscription as exempt in a state that taxes it can produce back-tax assessments reaching back several years, plus interest and penalties.
Bundled Software and Services
Many software deals combine taxable and non-taxable components. A maintenance contract that only provides upgrades and patches is generally taxed the same as a sale of prewritten software. A contract that provides only technical support with no software updates looks more like a non-taxable service. When one contract covers both without breaking out the charges, most states default to taxing the entire contract as a software sale.
The rule for both buyers and sellers is the same: itemize. Separate line items get separate tax treatment. Bundled prices tend to drag the whole transaction into the taxable column. This applies to maintenance contracts, implementation services paired with license fees, and training packages sold alongside subscriptions.
Which State’s Rate Applies
Even after a sale is determined to be taxable, sellers still have to figure out which jurisdiction’s rate applies. This is called sourcing. Most states use destination-based sourcing, meaning the tax rate is based on where the buyer receives or uses the software. About a dozen states use origin-based sourcing, tied to the seller’s location.
For remote sales across state lines, destination-based sourcing is the near-universal rule regardless of whether the seller’s home state is an origin state. A software company based in Texas selling a subscription to a customer in Illinois charges the Illinois rate applicable to the buyer’s location, not the Texas rate. Origin sourcing matters mainly for in-state sales in origin-based states, where the seller’s own local rate applies.
Software Used in Multiple States
Enterprise software creates a sourcing problem all its own. When a company buys a SaaS subscription or site license that employees in ten states will use at the same time, which state’s tax applies? The Streamlined Sales Tax Agreement addresses this through a Multiple Points of Use (MPU) exemption. A business buyer that knows at the time of purchase that the software will be used concurrently in more than one state can give the seller an MPU exemption certificate, which relieves the seller of the obligation to collect tax on the transaction.1Streamlined Sales Tax Governing Board. Multiple Points of Use (Section 312)
The buyer then apportions the purchase across each state where the software is used and remits use tax directly to each one. The apportionment method has to be reasonable, consistent, and supported by the buyer’s own business records. Companies often allocate based on the number of users or employees in each state. The compliance burden shifts from the seller to the buyer, and businesses with multi-state workforces need to plan for it.1Streamlined Sales Tax Governing Board. Multiple Points of Use (Section 312)
When a Seller Has to Collect Tax: Nexus
A state can only require a seller to collect its sales tax if the seller has “nexus” with that state. Before 2018, nexus was almost entirely a physical concept: a company with no office, warehouse, employees, or inventory in a state generally could not be compelled to collect its sales tax. The Supreme Court changed that in South Dakota v. Wayfair, Inc., ruling that states could establish nexus based purely on economic activity within the state.2Supreme Court of the United States. South Dakota v. Wayfair, Inc.
The South Dakota law at issue required out-of-state sellers to collect tax if they delivered more than $100,000 in goods or services into the state, or completed 200 or more separate transactions there, in a single year.2Supreme Court of the United States. South Dakota v. Wayfair, Inc. Most states adopted similar economic nexus rules after the decision. The thresholds have since diverged. Over a dozen states, including South Dakota itself, have dropped the transaction-count threshold entirely, leaving only the $100,000 revenue test. Others still use both. A software seller has to check current thresholds in each state, because assuming a uniform standard leads to missed filings.
Economic nexus hits software sellers particularly hard. A SaaS company with customers around the country can cross the $100,000 threshold in multiple states without ever setting foot in any of them. Once crossed, the seller has to register with the state’s tax department and begin collecting tax on all taxable sales into that state going forward. States share data and have grown more aggressive about identifying non-compliant remote sellers.
Sales Through Marketplaces
Developers selling through app stores or digital marketplaces may not have to handle collection themselves. Nearly every state with a sales tax has enacted marketplace facilitator laws shifting the collection and remittance obligation from the individual seller to the platform. If you sell a mobile app through a major app store, the platform typically collects and remits the tax on your behalf.
The details vary. Some states apply marketplace facilitator rules only to sales of tangible personal property, which can leave digital goods and SaaS in an ambiguous position. Others have broader statutes covering digital goods and services. Verify whether the platform actually collects tax in each state rather than assuming blanket coverage. Sales made through your own website or other direct channels remain your responsibility.
When the Buyer Owes Use Tax
If a software seller does not collect sales tax on a transaction, the buyer’s tax obligation does not disappear. It becomes a “use tax” owed directly by the purchaser to their home state. Use tax exists in every state that has a sales tax, at the same rate, to prevent buyers from dodging tax by purchasing from out-of-state sellers who lack nexus.
Individual consumers rarely self-report use tax, but businesses are expected to track and remit it. If your company buys a SaaS subscription from a provider that doesn’t charge sales tax, and your state taxes SaaS, your company owes use tax on the subscription. It usually goes on the company’s periodic sales and use tax return, or in some states on a separate form. Auditors look for exactly this gap, and it’s one of the most common findings in state audits of businesses.
Registration, Filing, and What Non-Compliance Costs
Once a seller establishes economic nexus in a state, registration is the immediate next step. Each state runs its own process, but sellers with obligations in multiple states can use the Streamlined Sales Tax Registration System (SSTRS), a free system that handles registration for sales tax permits across all participating member states in a single application.3Streamlined Sales Tax. Sales Tax Registration SSTRS
A few points about registration that catch sellers off guard:
- Registration is not amnesty. Signing up through the SSTRS does not erase liability for sales that should have been taxed before registration, unless a state specifically offers amnesty for voluntary registrants.3Streamlined Sales Tax. Sales Tax Registration SSTRS
- Zero-sales returns are still required. Once registered in a state, you file returns on that state’s assigned schedule even during periods with no taxable sales.3Streamlined Sales Tax. Sales Tax Registration SSTRS
- Filing happens state by state. The SSTRS handles registration, not filing. Returns and payments go directly to each state through its own system.3Streamlined Sales Tax. Sales Tax Registration SSTRS
Sellers registered through the SSTRS can also contract with a Certified Service Provider (CSP) that handles tax calculation, return preparation, filing, and remittance.3Streamlined Sales Tax. Sales Tax Registration SSTRS
The cost of getting it wrong stacks quickly. A seller that fails to register, fails to collect, or files late will generally face both a percentage-based penalty on the unpaid tax and interest accruing from the original due date. Monthly penalties of 5% to 10% of the unpaid amount are common, often capped at 25% to 50% of the total tax due. Interest runs on top, and many states peg their interest rates to the federal prime rate.
The more dangerous exposure is the look-back period. When a state discovers a seller should have been collecting but wasn’t, the assessment typically reaches back three to four years, sometimes longer if willful disregard can be shown. A SaaS company doing $500,000 in annual sales into a state with a 6% tax rate is looking at a potential $120,000 assessment for just four years of non-collection, before penalties and interest. That math is why proactive registration, even where the tax treatment of your product is ambiguous, often costs less than waiting to be discovered.