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How to Calculate Sales Tax for Online Sellers

A plain-English guide to sales tax for online sellers: nexus rules, marketplace facilitator laws, how to calculate tax on orders, and which states have no sales tax.

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Sales tax rules change frequently and vary by state and product type. This guide is for general education only. Consult a tax professional or CPA for your specific situation.

Formula

The math behind the result

Sales tax = sale price × tax rate

Tax-inclusive price: sale price = total ÷ (1 + rate)

Nexus threshold (most states): $100,000/year or 200 transactions

How it works

A clean flow from input to answer

  1. 1Determine where you have nexus — physical presence (office, warehouse, employees) or economic nexus (sales over $100K or 200 transactions in a state).
  2. 2Check if the state requires you to collect tax or if a marketplace facilitator (Etsy, Amazon, eBay) collects it on your behalf.
  3. 3Use the sales tax rate for the buyer's ship-to address (destination-based sourcing), not your own location.

FAQ

Common questions

Do I need to collect sales tax for online sales?

It depends on where you have 'nexus' — a significant connection to a state. After South Dakota v. Wayfair (2018), most states can require online sellers to collect tax if they exceed $100,000 in sales or 200 transactions per year in that state, even without a physical presence.

What is economic nexus?

Economic nexus means you've crossed a sales or transaction threshold in a state that triggers a sales tax collection obligation — even if you have no physical location there. Most states set the threshold at $100,000/year or 200 transactions.

Do I need to collect sales tax if I sell on Etsy or Amazon?

For most states, no. Etsy, Amazon, eBay, Walmart Marketplace, and Shopify Payments are 'marketplace facilitators' — they collect and remit sales tax on your behalf. You still need to track your own direct website sales.

Which states have no sales tax?

Five states have no state sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon. However, Alaska allows local municipalities to impose sales taxes.

Is sales tax based on where I am or where my customer is?

For remote sellers, sales tax is generally destination-based — you collect at the rate of the buyer's ship-to address, not your own location. This is the rule in most states.

Sales Tax Basics for Online Sellers

Sales tax is a consumption tax imposed by state and local governments on the sale of goods and some services. As an online seller, you may be required to collect sales tax from buyers in states where you have "nexus" — a legal connection that triggers tax obligations.

What Is Nexus?

Nexus comes in two forms:

  • Physical nexus: You have an office, warehouse, employees, or inventory stored in a state (e.g., an Amazon FBA warehouse storing your products in Texas gives you Texas nexus).
  • Economic nexus: After the 2018 South Dakota v. Wayfair Supreme Court ruling, nearly every state can require online sellers to collect sales tax once they exceed a sales threshold — typically $100,000 in annual sales or 200 transactions in that state.

Economic Nexus Thresholds by State

ThresholdStates
$100,000 or 200 transactionsMost states (Alabama, Arizona, California, Colorado, Florida, Georgia, Illinois, Michigan, New York, Ohio, Pennsylvania, Texas, Virginia, Washington, and more)
$100,000 onlyMassachusetts, North Carolina, Wisconsin, and others (dropped the 200-transaction threshold)
No sales taxAlaska, Delaware, Montana, New Hampshire, Oregon

Marketplace Facilitator Laws

If you sell on Etsy, Amazon, eBay, Walmart Marketplace, or Shopify Payments, you likely don't have to worry about collecting sales tax for marketplace sales — the platform does it for you.

Under marketplace facilitator laws (now in effect in every US state with sales tax), the marketplace is responsible for collecting and remitting sales tax on your behalf. This means:

  • Etsy collects sales tax on all Etsy orders in every US state
  • Amazon collects on FBA and Amazon-fulfilled orders
  • eBay collects in all applicable states

Important: If you also sell through your own website or Shopify store (not Shopify Payments), you are responsible for collecting tax on those direct sales once you hit nexus thresholds.

How to Calculate Sales Tax on an Order

Sales tax is typically destination-based — you charge the rate for the buyer's ship-to address. Use the Sales Tax Calculator to look up the rate for any US state and calculate the tax on any sale amount.

Example: A buyer in California (7.25% state rate, plus local district taxes averaging ~2%) buys a $50 item.

  • State sales tax: $50 × 7.25% = $3.63
  • Local district taxes vary — most of California is 8.25%–10.25%
  • At 9.5% total: $50 × 9.5% = $4.75 tax

Steps to Get Sales Tax Compliant

  1. Determine your nexus states. Start with your home state (always nexus) and any state where you store inventory or have employees.
  2. Check economic nexus thresholds. Review your sales data to see if you've crossed $100K or 200 transactions in any state.
  3. Register for a sales tax permit in each nexus state before you start collecting. Collecting without a permit is illegal in most states.
  4. Set up tax collection in your shopping cart/store platform.
  5. File and remit. File sales tax returns on the schedule each state requires (monthly, quarterly, or annually depending on your sales volume).

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