Amazon now adds Washington state ad tax

TL;DR

If you’re running online ads from Washington, there’s a new sales tax in town — and it could hit your margins hard.

Advertisers are now required to charge sales tax on ad spend billed to Washington addresses. It’s part of a broader push to tax digital services in WA. ^[1]

What changed

It started with a bill — and a billing address.

• In May 2025, Washington passed Senate Bill 5814, ^[2] expanding sales tax to cover digital and service-based business activities.
• That includes advertising services like online ad production, placement, sponsored ads, and display campaigns.
• Starting October 1, digital ad platforms like Amazon ^[3] and Meta ^[4] began charging WA sales tax on ads billed to customers with Washington addresses.
• Currently, the tax applies when the customer’s billing address is in Washington State.

Why this will hit WA-based seller budgets and margins hard

With advertising services now reclassified as taxable retail sales, ^[5] sellers based in cities like Seattle could see digital ad spend taxed at a combined rate of up to 10.4%.

Here’s how that adds up.

• Let’s say your Q4 digital ad spend budget is $15,000.
• The combined tax in some Seattle districts can now reach 10.4% — made up of 6.5% state, 3.85% city, and 0.90% special district taxes. (Read more: TaxCloud Sales Tax Guide to Seattle, June 2025)
• So if you’re billed in Seattle, you could incur an extra $1,560 in tax on that $15,000 spend — with no increase in clicks, reach, or ROI.

That’s not a higher CPC. That’s tax.

And with Black Friday and the holiday season coming, it’s going to eat into margins fast.

Who this affects

• Sellers and advertisers billed in Washington — your digital ad spend now incurs retail sales tax
• Agencies managing ad spend for Washington-based clients — tax is tied to the client’s billing address
• Finance teams forecasting Q4 campaign budgets — this change could skew cost assumptions
• Advertisers outside Washington — you’re not being charged (yet), but other states may follow

Why this matters

This isn’t just a one-off.

It’s part of a growing movement to tax the digital layer of commerce:

• Washington’s bill SB 5814 ^[2] also expanded retail sales tax to custom software (and maintenance), IT support, staffing, website development, live presentations, and security services
• Amazon is complying, but Comcast filed suit in September 2025, arguing parts of SB 5814 are unconstitutional ^[6]
• If the lawsuit succeeds, it could delay or overturn parts of the law — but for now, sellers are being charged
• However, if Washington’s new sales tax rules on digital advertising stand, other states may follow WA’s lead and tax digital advertising too. (This is how marketplace facilitator laws started, too — Washington made the first move in 2018, and the rest followed.) ^[7]

Next steps for sellers

• Check your billing address on Amazon, Meta, and other platforms. If it’s in Washington, you’re now paying sales tax on ads.
• Adjust your Q4 budgets — especially if you’re planning holiday campaigns.
• Double-check billing settings — if you’re working with an agency, confirm which address is on file.