Washington State Capital Gains Tax, Explained

Washington has no general income tax; your salary, bonuses, and business income owe the state nothing. What it has instead is a capital gains excise tax with an unusually narrow footprint: it applies only to long-term gains, only to individuals (gains flowing through pass-through entities are attributed to the individual owners), and only above a large standard deduction: $278,000 for 2025, indexed annually for inflation. The 2026 deduction hadn't been published by the Department of Revenue as of this writing.

Two structural quirks follow. First, because the deduction is annual and generous, most Washingtonians never owe this tax in their lives; it's aimed at large realization events: the concentrated-stock unwind, the startup exit, the eight-figure portfolio rebalance. Second, short-term gains are simply outside the tax. Washington's system doesn't reward holding the way the federal system does; it just doesn't reach gains on assets held a year or less. (Federal ordinary rates still punish short-term selling harder than anything Olympia does; see the federal brackets guide.)

The exemptions are the headline. All real estate is exempt: primary homes, rentals, commercial property, land. The exemption extends to gains attributable to real estate held through a privately-held entity, so an LLC holding apartment buildings doesn't change the answer. A Seattle landlord can sell a portfolio at any gain and owe Washington's capital gains tax nothing. The federal side is another story; recapture and federal capital gains still apply, which is where a 1031 exchange and the depreciation calculator earn their keep.

Retirement accounts are exempt too: assets held in retirement accounts never generate this tax, regardless of trading activity or gain size inside the account. Rebalancing a $5 million IRA is a Washington non-event.

Put the two together and the planning geography becomes clear: the tax concentrates on taxable brokerage accounts and business-sale proceeds. Where your assets sit determines your exposure far more than how much you're worth.

For years the tax was a flat 7% above the deduction. Legislation in 2025 added a second tier: an extra 2.9% on taxable gains above $1 million, bringing the marginal rate on those dollars to 9.9%. Note the base: the $1 million line is measured on taxable gains, after the standard deduction, so with the 2025 deduction, the surtax starts once your total long-term gains pass roughly $1,278,000.

One more moving part: Washington provides a separate deduction for certain donations to qualified organizations, subject to statutory thresholds and limits. Use the return-year instructions and actual donation records before including it in a projection.

A single Seattle engineer sells long-held company stock for a $1.5 million long-term gain in 2025. Using the 2025 deduction figure:

• Taxable gain: $1,500,000 − $278,000 deduction = $1,222,000
• First $1,000,000 of taxable gain × 7% = $70,000
• Remaining $222,000 × 9.9% (7% + the 2.9% surtax) = $21,978
• Washington total: $91,978, about 6.1% of the whole gain

The federal layer is bigger. Assuming her salary already fills the top bracket and the NIIT threshold: 20% × $1.5M = $300,000, plus 3.8% NIIT × $1.5M = $57,000, for $357,000 federal. All-in: roughly $449,000, or 29.9% of the gain. Washington is the smallest slice, but it's also the only slice you can eliminate with timing alone, as the next section shows.

• Spread sales across tax years. Realizing up to the standard deduction each year, instead of one giant year, can keep every dollar at 0% Washington tax. For a multi-million-dollar position, a two-to-four-year unwind plan is often worth six figures against the excise.
• Respect the $1 million taxable-gain line. If a single-year sale is unavoidable, sizing it so taxable gains stay under $1M keeps the 2.9% surtax off the top slice.
• Mind where assets sit. Gains inside retirement accounts are exempt, so realization-heavy strategies (rebalancing, active trading) belong in retirement accounts, while the taxable account holds what you intend to keep.
• Real estate plays by federal rules only. Since Washington exempts property sales entirely, the sell-vs-hold decision on a rental is purely a federal calculation; our sell-or-rent framework covers it.
• Plan the payment, not just the tax. A gain big enough to owe Washington is big enough to create a federal estimated-payment problem in the same quarter; coordinate both bills before the sale closes, and confirm Washington's own filing deadline for the year you sell.