オンライン販売者としてどの売上税率を顧客に課すべきかを理解することは容易ではありません。まずは、売上税率がどのように決まるか、またビジネスが拠点を置く州にいる顧客にどの税率を課す必要があるか (州内売上) を理解することが重要です。これを判断するには、自社のオンラインビジネスの拠点を置く州が、起点ベースと仕向地ベースのどちらであるかを調べます (この概念は「売上税ソーシング」と呼ばれます)。

この記事の内容

• 売上税ソーシングの概要
  
• 起点ベースの州と仕向地ベースの州
  
• さまざまな種類の売上税ソーシングの例
  

売上税ソーシングの概要

州は通常、次の 2 つの方法のうちどちらかで売上税を徴収することを販売者に義務付けています。

• 起点ベースの徴収
  
• 仕向地ベースの徴収
  

起点ベースの売上税ソーシングを採用している州に拠点を置く販売業者は、そのビジネスの拠点地で売上税を徴収する必要があります。ビジネスの拠点が起点ベースの州にある場合は、その州内のすべての顧客に対して、ビジネスの所在地の合計税率を課します。合計税率とは、州の売上税率に、群、市、地区の税率を加算した合計です。たとえば、ビジネスの所在地がアリゾナにある場合は、アリゾナのすべての顧客に対して、同じ合計売上税率を課します。事業者はその州のすべての顧客に対して同じ売上税率を課せばよいため、これが売上税ソーシングの最も簡単な形式と考えられています。

仕向地ベースの売上税ソーシングはより複雑です。仕向地ベースの売上税ソーシングの場合、販売業者は、顧客の住所における合計売上税率を課す必要があります。州内には数百もの税管轄区域がある場合があるため、同じ州でも顧客によって税率が大きく異なることになります。たとえば、ビジネスの所在地がワシントンにある場合は、すべての顧客に対して、6.50% の州売上税率に、各顧客の所在地で適用される地域売上税を加えた合計を課すことになります。

起点ベースの州と仕向地ベースの州

さまざまな種類の売上税ソーシングの例

起点ベースの州で売上税率を正確に計算する方法を示す例をご紹介します。このビジネスの所在地はテキサス州のアービングにあります。

テキサス州の税率: 6.25%
アービングの売上税率: 1%
ダラス MTA (売上税を課すメトロポリタン・トランジット・オーソリティ): 1%
合計売上税率: 8.25%
ビジネスの在住地がアービングでなくても、この事業者は、テキサスのすべての顧客に 8.25% を課します。

ニューヨーク州ニューヨーク市を所在地とするビジネスには、仕向地ベースの売上税ソーシングが次のように適用されます。この事業者が、ニューヨーク州バッファローに所在する顧客に対して販売を行いました。

ニューヨーク州の税率: 4%
エリー群の税率: 4.75%
合計売上税率: 8.75%。これは、この事業者が、バッファローに所在するこの顧客に課す税率です。

一方、同事業者が、ニューヨーク州ロチェスターに所在する顧客に対して別の販売を行ったとします。

ニューヨーク州の税率: 4%
モンロー群の税率: 4%
合計売上税率: 8%。これは、この事業者が、ロチェスターに所在するこの顧客に課す税率です。

これらの例は、事業者の所在地がある州と同じ州の顧客に販売する場合にのみ適用されます。他の州に所在する顧客に販売する場合は、売上税を課す際に他の規則に従う必要がある場合があります。通常は、顧客の所在地での税率で売上税を課します (州際取引は仕向地ベースのソーシング)。

What to do if you have sales tax nexus in another state

If your business has expanded to the point where you have a certain number of sales in a state beyond your home base, your tax obligations will increase. In the world of ecommerce, this is usually triggered by “economic nexus,” which typically occurs once you cross a certain sales threshold.

If you realize you’ve crossed a threshold in a new state, follow these steps immediately.

• Register for a permit: Do not collect a cent of sales tax until you have registered with that state’s Department of Revenue. Collecting tax without a permit is illegal.

• Update your shopping cart: Once registered, configure your checkout software to apply the correct destination-based rates for that state.

• Collect and remit: Start collecting the tax on all taxable sales and file your returns according to the state's assigned frequency (monthly, quarterly, or annually).

Because tax laws are updated frequently, you need reliable sources for your sales tax rate determination. Some resources for determining sales tax rate include state department of revenue websites, tax automation or payments platform, or the Streamlined Sales Tax website for states that have worked to standardize rules for remote sellers.

Examples of states with unique sales tax sourcing requirements

Here’s an example of how the correct sales tax rate is calculated in an origin-based state. This business is located in Irving, Texas.

• Texas state rate: 6.25%
  
• Irving sales tax rate: 1.00%
  
• Dallas MTA (Metropolitan Transit Authority that imposes a sales tax): 1.00%
  
• Combined sales tax rate: 8.25%
  

This business should charge all customers in Texas 8.25%, even if they are located outside of Irving.

Here’s how destination-based sales tax sourcing works for a business located in New York City, New York.

The business made a sale to a customer located in Buffalo, New York.

• New York state rate: 4.00%
  
• Erie County rate: 4.75%
  
• Combined sales tax rate: 8.75%
  

This is what the business would charge the customer in Buffalo.

However, they make another sale to a customer located in Rochester, New York.

• New York state rate: 4.00%
  
• Monroe County rate: 4.00%
  
• Combined sales tax rate: 8.00%
  

This is the rate the business would charge this customer in Rochester.

These examples only apply to selling to customers in the state where your business is located. If you have sales to customers located in other states, then you may need to follow different rules when charging sales tax. In general, you would charge sales tax at the rate where your customer is located (destination-based sourcing for interstate transactions).

Several states employ hybrid systems that can challenge even seasoned sellers. These states don't fit neatly into one category, making them the most complex places to manage sales tax:

• California: California is unique because it uses a hybrid system. Generally, state, city, and county taxes are sourced to the origin (your business location), but district taxes are sourced to the destination (the buyer's location). This mixed sourcing means your tax rate might stay the same for some components but shift for others.

• Illinois: As of January 1, 2026, Illinois has a complex structure. If you have “predominant selling activities” in-state, you use origin rules. However, remote sellers must use destination rules. Furthermore, Illinois recently implemented a 15% tax rate penalty for sellers who fail to provide the exact destination information required on their ST-2 forms.

• Colorado: While Colorado uses destination sourcing, it also imposes a retail delivery fee on any sale delivered by motor vehicle. Additionally, as of 2026, Colorado has eliminated the “vendor fee” (a discount sellers used to keep for filing on time) at the state level, meaning you must now remit 100% of the collected state tax.

• Florida: Florida generally follows destination-based rules, meaning you charge the 6% state rate plus the local discretionary sales surtax of the buyer’s county. However, Florida has a unique bracket rule: for sales of a single item of tangible personal property, the local county surtax only applies to the first $5,000 of the purchase price. Anything above that amount is only subject to the 6% state rate.

How Stripe Tax can help

Stripe Tax reduces the complexity of tax compliance so you can focus on growing your business. Start collecting taxes globally by adding a single line of code to your existing integration, clicking a button in the Dashboard, or using our powerful API.

Stripe Tax helps you monitor your obligations and alerts you when you exceed a sales tax registration threshold based on your Stripe transactions. It can also register to collect tax on your behalf in the US and manage filings through trusted partners. Stripe Tax automatically calculates and collects sales tax, VAT, and GST on:

• Digital goods and services in all US states and over 100 countries
  
• Physical goods in all US states and 42 countries
  

Stripe Tax can help you:

• Understand where to register and collect taxes: See where you need to collect taxes based on your Stripe transactions. After you register, switch on tax collection in a new state or country in seconds. You can start collecting taxes by adding one line of code to your existing Stripe integration, or add tax collection with the click of a button in the Stripe Dashboard.

• Register to pay tax: If you need to register for a sales tax in the US, let Stripe manage your tax registrations. You’ll benefit from a simplified process that prefills application details—saving you time and simplifying compliance with local regulations. If you need help registering outside of the US, Stripe partners with Taxually to help you register with local tax authorities.

• Automatically collect tax: Stripe Tax calculates and collects the right amount of tax owed, no matter what or where you sell. It supports hundreds of products and services and is up-to-date on tax rules and rate changes.

• Simplify filing: Stripe Tax seamlessly integrates with filing partners, so your global filings are accurate and timely. Let our partners manage your filings so you can focus on growing your business.

Learn more about Stripe Tax, or get started today.