Washington Sales Tax and Invoicing Rules for 2026

TL;DR: Washington state has a 6.5% state sales tax with local additions pushing combined rates to 7.0%–10.6%. There is no state income tax, making sales tax critical. Economic nexus applies at $100,000 in sales. Washington taxes most digital goods and SaaS.

State sales tax rate

Washington imposes a 6.5% state sales tax. Cities and counties add local taxes that vary significantly — combined rates range from 7.0% to 10.6% depending on the location.

Seattle's combined rate is approximately 10.25%. Tacoma sits around 10.2%. Rural areas may be closer to 7.7%–8.0%.

Washington uses destination-based sourcing — you charge the rate at the buyer's delivery address. With hundreds of local taxing districts, address-level rate lookups are essential. Washington participates in the Streamlined Sales Tax system.

Nexus rules

Physical nexus applies through offices, employees, inventory, or property in Washington.

Economic nexus triggers at $100,000 in gross retail sales to Washington buyers in the current or prior calendar year. There is no transaction count threshold.

Washington also has click-through nexus and affiliate nexus provisions. Marketplace facilitators must collect and remit on behalf of third-party sellers. Washington is aggressive about enforcement — the state has no income tax and depends heavily on sales tax and B&O tax revenue.

Invoice requirements

The Washington Department of Revenue requires sellers to maintain records of all transactions. Invoices should include:

• Seller's name, address, and registration number (UBI number)
• Date of sale
• Buyer information
• Description of goods or services
• Sale price
• Tax rate by location
• Tax amount (separately stated)
• Total

Because of the many local taxing jurisdictions, your records should capture the specific delivery address for each sale to support the rate charged. For exempt sales, retain the buyer's Resale Certificate or exemption documentation. Records must be kept for at least five years.

Exemptions and special cases

Groceries (food for home consumption) are exempt. Prescription drugs are exempt. Clothing is fully taxable — Washington has no clothing exemption.

Manufacturing machinery and equipment used directly in manufacturing is exempt. SaaS and digital goods are fully taxable in Washington — the state taxes digital automated services (SaaS), digital goods (e-books, music, video), and remote access software. This is one of the broadest digital taxation regimes in the U.S.

Washington has no state income tax, which means the sales tax base is intentionally wide. Business services are generally not taxable for sales tax purposes, but they may be subject to Washington's separate Business & Occupation (B&O) tax.

Filing frequency and deadlines

Washington assigns frequency based on liability:

• Monthly — most businesses
• Quarterly — smaller liability
• Annually — very small sellers

Monthly returns are due the 25th of the following month. Quarterly returns are due the last day of the month following the quarter (April 30, July 31, October 31, January 31). Annual returns are due April 15.

Returns combine sales tax with the B&O tax on the same filing. Electronic filing through My DOR is required for most filers.

Penalties for non-compliance

Late filing incurs a 5% penalty on unpaid tax for each month (up to 25%). A 5% assessment penalty applies to deficiencies discovered on audit.

Interest accrues at the rate set by the Department. Washington is known for active enforcement — the state audits aggressively, particularly targeting remote sellers and digital goods providers.

FAQ

Is SaaS taxable in Washington state?

Yes. Washington classifies SaaS as a "digital automated service" and taxes it at the full combined rate. This includes cloud-based software, hosted applications, and any software accessed remotely. If you sell SaaS to Washington customers, you must collect sales tax.

What is the B&O tax and how does it relate to sales tax?

The Business & Occupation tax is a separate gross receipts tax on business activity in Washington — it applies to your gross income, not profits. It is filed alongside sales tax but is a distinct obligation. B&O tax rates vary by business classification.

How do I determine the correct local rate with so many jurisdictions?

Use the Washington Department of Revenue's free online tax rate lookup tool or integrate their tax rate database into your invoicing system. Address-level lookup is necessary because rates can differ within the same city. InvoiceQuickly's rate lookup can also help.

Check the precise combined rate for any Washington address with InvoiceQuickly's rate lookup.