Washington Income & Tax for eCommerce Businesses
💡 Double Trigger — One Threshold, Two Taxes: Crossing Washington's $100,000 economic nexus threshold triggers BOTH sales tax collection obligations AND B&O tax liability simultaneously. Most sellers focus on sales tax and get blindsided by the B&O tax. Since B&O tax applies to gross receipts with no deductions for expenses or cost of goods, even thin-margin sellers owe it once the threshold is crossed.
Part 1: Washington Business & Occupation (B&O) Tax
Washington's B&O Tax is a gross receipts tax on the privilege of doing business in the state. Unlike an income tax, there are no deductions for labor, cost of goods, or business expenses. You pay based on total revenue from Washington sources, period. This can be a meaningful burden for high-revenue, lower-margin sellers like eCommerce businesses.
B&O Tax Rates by Classification
B&O tax rates vary based on business activity classification. The most relevant rates for eCommerce sellers are:
Retailing (selling tangible goods to end consumers): 0.471% of gross receipts
Wholesaling (selling to other businesses for resale): 0.484% of gross receipts
Service & Other Activities: 1.5% of gross income — important for sellers of digital products or services
Effective October 1, 2025, Washington updated its B&O rates for service businesses on a progressive scale: 1.5% for companies with less than $1 million in affiliated group gross income; 1.75% for $1M–$5M; and 2.1% for amounts exceeding $5M in affiliated group income.
Who Has B&O Tax Nexus?
An out-of-state business has Washington B&O tax nexus when it meets any of the following during the current or prior calendar year:
Generates more than $100,000 in combined gross receipts sourced or attributed to Washington (from any and all Washington income, including retail, wholesale, and services)
Has physical presence in Washington — employees, inventory, office, or property
Is organized or commercially domiciled in Washington
Importantly, the $100,000 threshold for B&O tax applies to all Washington income combined — not just retail sales. If you generate $60,000 in retail sales and $50,000 in services to Washington customers, your combined $110,000 exceeds the threshold.
Does PL 86-272 Apply?
No. Federal Public Law 86-272 protects businesses from state income-based taxes. Because Washington's B&O Tax is a gross receipts tax — not an income tax — PL 86-272 provides no protection. Out-of-state sellers who cross the $100,000 threshold owe B&O tax regardless of whether their only Washington activity is soliciting orders for tangible goods.
Part 2: Washington Sales Tax
Economic Nexus — Same $100,000 Threshold
Washington uses the same $100,000 threshold for both B&O tax and sales tax nexus. The calculation includes all Washington sales — including marketplace-facilitated sales through Amazon, Etsy, and similar platforms — even though the marketplace collects the sales tax on those specific transactions.
Critical point: Even if Amazon collects all your Washington sales tax on FBA sales, you must still count those sales when determining if you've crossed the $100,000 threshold. If your total Washington revenue (FBA + Shopify + other channels) exceeds $100,000, you must register for sales tax on your direct sales AND file B&O tax returns.
Washington Sales Tax Rates
Washington's base state sales tax rate is 6.5%. Local jurisdictions add additional taxes, with combined rates ranging from 6.5% to 10.4% depending on the customer's city and county. Washington has some of the highest combined sales tax rates in the country, particularly in the Seattle metro area. The state is destination-based — you charge based on the customer's delivery address.
FBA Sellers in Washington
Amazon's headquarters and major fulfillment infrastructure are in Washington State. FBA sellers with inventory in Washington warehouses have immediate physical nexus for both B&O tax and sales tax, regardless of their revenue level. Even sellers below the $100,000 economic threshold can have Washington obligations if they have physical inventory there.
The Small Business B&O Credit
Washington provides a Small Business B&O Tax Credit that reduces or eliminates B&O tax for very small businesses. The credit phases out as gross receipts increase. For businesses that have crossed the $100,000 economic nexus threshold, the credit is generally no longer available — but it's worth confirming with a tax advisor if you're just over the threshold.
What About Sales Tax?
Washington's destination-based rate system — with combined rates up to 10.4% in some areas — and its unique requirement to count marketplace sales toward the nexus threshold make it one of the more complex sales tax states for eCommerce sellers.
At Tall Oak Advisors, we put together this guide as a resource for our eCommerce community. Tax rules vary significantly from state to state, and we want sellers to have the information they need to make informed decisions. More info at talloakadvisors.com
Disclaimer: The information in this article is for general informational purposes only and does not constitute legal or tax advice. Tax laws change frequently. Consult a qualified tax advisor or CPA regarding your specific situation.
Sources: RCW 82.04 (B&O Tax); RCW 82.08 (Sales Tax); WA Dept. of Revenue — Remote Sellers (eff. Jan. 1, 2020); WA Dept. of Revenue — Out-of-State Business Reporting Thresholds; Pub. L. No. 86-272 (not applicable to B&O).
