Sales Tax Calculator

How US sales tax actually works

Sales tax in the US is a patchwork. Five states have no state-level sales tax: Delaware, Montana, New Hampshire, Oregon, and Alaska (though some Alaskan boroughs collect local tax). Most other states have a base state rate, and cities and counties layer local taxes on top. The combined rate is what you actually collect at the register. Rates in this calculator are combined state + local averages — specific-address rates can be up to 2% higher.

For the most accurate number, look up the specific ZIP or city rate through your state's revenue department or an address-level rate API (TaxJar, Avalara, Stripe Tax). The calculator lets you override the average with a custom rate when you know the exact city rate for a transaction.

When small businesses have to collect sales tax (post-Wayfair reality)

The rule used to be simple: physical presence (store, office, warehouse) in a state triggered collection. After South Dakota v. Wayfair in 2018, that changed. Every state with sales tax now has an "economic nexus" threshold — typically $100,000 in sales or 200 transactions per year. Hit the threshold and you must register, collect, and remit tax in that state within 30–60 days.

For most small businesses, this creates a compliance mess. A Shopify store shipping to all fifty states can easily cross $100,000 in three or four states and suddenly owe registration and filing in each. Services are often exempt, but not always — some states tax certain services. If you're crossing $500,000/year in out-of-state sales, a sales tax automation tool is the single best $50–150/month you can spend. It pays for itself the first time you'd otherwise miss a filing.

Taxable vs exempt items

• Usually taxable: physical goods, prepared food, digital products (varies by state), SaaS (about 20 states), personal services in some states.
• Usually exempt: groceries (in many states), prescription drugs, clothing (in PA, NJ, MN, MA, VT), most services, resale purchases (with resale certificate).
• Special cases: dietary supplements taxed differently from food, "ready to eat" food often taxed while grocery isn't, tangible vs digital books treated differently.

If you're not sure whether an item is taxable, check your state's revenue site for "taxability matrix." Most states publish one. If the matrix is ambiguous (and many are), call the state — most revenue departments will tell you the answer in writing via email, which is your audit defense.

Collecting sales tax on invoices

If you sell services, invoice the correct state and city rate based on where the client is located (destination sourcing, most states) or where the service is performed (origin sourcing, a few states). Use our invoice generator and enter the tax rate returned by this calculator into the tax field. Always show tax as a separate line — never bury it in the subtotal, since clients and their AP teams need to see it broken out to verify.

How to file and remit sales tax

Each state has its own filing cadence — monthly, quarterly, or annual depending on volume. Most require filing even in zero-tax months. Penalties for late filing are steep; states rely on sales tax revenue and aggressively pursue non-filers. The practical minimum setup for a small business with multi-state sales:

1. Register in every state where you have nexus (physical or economic).
2. Set up automated tax collection at checkout (Shopify Tax, Stripe Tax, TaxJar, Avalara).
3. File returns on the schedule each state requires — calendar every due date.
4. Remit collected tax by the deadline. Most states accept ACH; a few still require paper checks.
5. Keep records for at least three years — four in California, four in Louisiana, three everywhere else.
6. File zero returns when you had no sales in a state where you're registered. Skipping these triggers penalty letters.

Sales tax holidays and promotions

Many states run annual sales tax holidays — back-to-school items, emergency supplies, energy-efficient appliances. If your products fall in a holiday category, tax is waived for that weekend. These are often good promotional windows even for single-state businesses since consumers actively shop during them. Texas's August back-to-school holiday and Florida's emergency supplies holiday are the biggest annually.

Marketplace facilitator laws — what they cover and what they don't

If you sell through Amazon, Etsy, eBay, or Walmart Marketplace, the marketplace itself collects and remits sales tax for you in every US state with tax. This simplifies life but creates reporting quirks. You still owe income tax on the sale. In a few states (Washington, Colorado) you still owe a business license or "gross receipts" tax based on the sale even though you didn't handle the sales tax. If you sell both through marketplaces and your own Shopify store, segregate channel reporting — the income-tax treatment is identical but the sales-tax treatment is completely different.

Common sales tax mistakes (in order of cost)

• Collecting but not remitting. Sales tax is a pass-through — never spend it. Keep it in a separate bank account. Non-remittance can pierce corporate liability protection in every state.
• Wrong rate. Using the state rate when you needed combined state + local. The calculator above defaults to the combined average — close, but for compliance use address-level rates from a paid provider.
• Not registering when you cross nexus thresholds. States are notified by platforms (Shopify, Amazon); you will get a letter if you don't register proactively.
• Charging tax on exempt items. Taxing groceries in a state that exempts them creates refund liability to every customer — class actions have been filed on this.
• Charging non-nexus state customers. You shouldn't be collecting for states you don't have nexus in. That tax isn't remittable to anyone and owes back to the customer.
• Mixing SaaS and physical goods under one rate. Different taxability. Separate them on the invoice.

Rate reference (combined state + local averages)

The dropdown includes all fifty states plus DC, using approximate combined state + local rates. High-rate states include Louisiana (9.55%), Tennessee (9.55%), Arkansas (9.47%), Washington (9.40%), and Alabama (9.29%). Zero-rate states: Oregon, Montana, New Hampshire, Delaware, and Alaska (state only — localities vary). Most mid-rate states cluster between 6.5% and 8.0%.

For estimated taxes on income (federal + state), use our quarterly tax estimator. For pricing products with tax already baked into the experience, combine this calculator with the pricing strategy planner to see after-tax consumer price.