To estimate Washington state estate tax, subtract the 2026 exclusion of $3,076,000 from the net estate (gross assets minus deductions), then apply Washington’s progressive brackets, which run from 10% on the first $1,000,000 of taxable estate up to 35% on amounts over $9,000,000. The rate schedule changed on July 1, 2025, so any online Washington state estate tax calculator built on the old 10%–20% brackets will understate the bill, often by six figures.
The 2025–2026 Rate Brackets
Washington’s current estate tax brackets apply to all deaths on or after July 1, 2025. They operate on the “Washington taxable estate,” meaning the gross estate minus deductions minus the applicable exclusion amount.1Washington Department of Revenue. Estate Tax Tables
- $0 – $1,000,000: 10%
- $1,000,001 – $2,000,000: 15%
- $2,000,001 – $3,000,000: 17%
- $3,000,001 – $4,000,000: 19%
- $4,000,001 – $6,000,000: 23%
- $6,000,001 – $7,000,000: 26%
- $7,000,001 – $9,000,000: 30%
- Over $9,000,000: 35%
The exclusion itself is $3,076,000 for 2026, adjusted annually for inflation from a $2,193,000 base set for deaths on or after January 1, 2022.2Washington State Legislature. RCW 83.100 – Estate and Transfer Tax Act Check the threshold for the specific year of death, because the figure shifts each January.
How to Calculate the Tax
The sequence is the same whether you run it on paper or in a spreadsheet.
- Add every asset at fair market value on the date of death. That is the gross estate.
- Subtract allowable deductions: marital, charitable, farm, qualified family-owned business, debts, funeral costs, and administration expenses.
- Subtract the $3,076,000 exclusion. The result is the Washington taxable estate.
- Apply each bracket to its slice of the taxable estate and sum the pieces.
Only the amount above $3,076,000 is taxed, and only the portion inside each bracket is taxed at that bracket’s rate. The 35% top rate does not apply to the whole estate; it applies only to dollars above $9,000,000 of taxable estate.
Example: $5,000,000 Gross Estate
A Washington resident dies in 2026 with $5,000,000 in assets, no surviving spouse, and no deductions beyond the exclusion.
Taxable estate: $5,000,000 − $3,076,000 = $1,924,000.
- First $1,000,000 × 10% = $100,000
- Remaining $924,000 × 15% = $138,600
Washington estate tax: $238,600.
Example: $8,000,000 Gross Estate
Same assumptions, larger estate.
Taxable estate: $8,000,000 − $3,076,000 = $4,924,000.
- $0 – $1,000,000 × 10% = $100,000
- $1,000,001 – $2,000,000 × 15% = $150,000
- $2,000,001 – $3,000,000 × 17% = $170,000
- $3,000,001 – $4,000,000 × 19% = $190,000
- $4,000,001 – $4,924,000 × 23% = $212,520
Washington estate tax: $822,520. That is about 10.3% of the gross estate, and it is a number most families underestimate before they sit down with the brackets.
What Counts in the Gross Estate
Washington uses the federal definition of “gross estate” from Section 2031 of the Internal Revenue Code: everything the decedent owned or had an interest in at death, at fair market value on that date.3Office of the Law Revision Counsel. 26 U.S. Code 2031 – Definition of Gross Estate The net is wide:
- Real estate, in Washington or elsewhere for residents
- Bank accounts, brokerage accounts, stocks, bonds, and mutual funds
- Ownership stakes in closely held businesses, partnerships, and LLCs
- IRAs, 401(k)s, and similar retirement accounts
- Life insurance proceeds from policies the decedent owned or controlled
- Vehicles, jewelry, collectibles, and household goods
Life insurance catches many families off guard. If the decedent held “incidents of ownership” (the power to change beneficiaries, borrow against the policy, or cancel it) the full death benefit counts.4Washington Department of Revenue. Estate Tax FAQ A $500,000 policy can push an otherwise non-taxable estate over the threshold. Policies owned by an irrevocable life insurance trust, where the decedent surrendered control more than three years before death, are not included.
Washington is a community property state. For married decedents, generally only the decedent’s one-half share of community property enters the gross estate; the surviving spouse’s half does not. Separate property is included in full. Classifying property correctly matters because it sets the starting number for everything that follows.
Deductions That Reduce the Taxable Estate
After you tally the gross estate, deductions do most of the work in bringing the tax down.
Marital Deduction
Property passing outright to a surviving spouse qualifies for an unlimited marital deduction, which typically eliminates Washington estate tax on those transfers. The framework follows federal IRC Section 2056.5Office of the Law Revision Counsel. 26 U.S. Code 2056 – Bequests, Etc., to Surviving Spouse Property placed in a qualifying terminable interest property (QTIP) trust can also qualify if the executor makes a timely, irrevocable QTIP election on the return.6Washington Department of Revenue. Estate Tax Qualified Terminable Interest Property
Washington does not allow portability of unused exclusion between spouses.4Washington Department of Revenue. Estate Tax FAQ Each spouse gets only their own $3,076,000. If the first spouse to die leaves everything to the survivor without using any state exclusion, that exclusion is lost. For married couples with combined estates above the exclusion, credit shelter trusts and similar structures become significantly more important as a result.
Charitable Deduction
Bequests to qualified charities reduce the gross estate dollar for dollar, with no cap.
Farm Property Deduction
Washington allows a deduction of up to $6 million for qualified farm property, defined as real and personal property used for farming and valued at $2 million or less per parcel. Heirs must sign a covenant keeping the property in agricultural use for at least ten years after death; breaking the covenant triggers clawback of the tax savings.7Washington State Legislature. RCW 83.100.046 – Deduction for Qualified Farm Property
Qualified Family-Owned Business Deduction
Family businesses can qualify for a deduction of up to $2.5 million. The business interests must be worth $6 million or less, must represent more than 50% of the taxable estate, and the decedent or a family member must have materially participated in the business for at least five of the eight years before death.8Washington State Legislature. RCW 83.100.048 – Deduction for Qualified Family-Owned Business Interests
Who Has to File
A Washington estate tax return is required whenever the gross estate meets or exceeds the applicable exclusion, which is $3,076,000 for 2026.1Washington Department of Revenue. Estate Tax Tables Two groups file: Washington residents whose worldwide estate meets the threshold, and nonresidents who own Washington real estate or tangible personal property.9Washington Department of Revenue. Estate Tax A return is required even when deductions wipe out the tax.
One narrow exception: if the decedent was survived by a spouse, the qualifying family residence passed to that spouse, and the rest of the estate (minus the residence) is below the exclusion, no return is needed.10Washington State Legislature. RCW 83.100.050 – Estate Tax Return Filing Requirement
Deadline, Penalties, and Interest
The return and the tax payment are both due nine months after the date of death.11Washington State Department of Revenue. Application for Extension of Time to File a Washington State Estate and Transfer Tax Return A filing extension does not extend the time to pay.
Late filing penalties run 5% of the tax due for each month or partial month overdue, capped at 25%.12Washington State Legislature. WAC 458-57-035 – Penalties and Interest On a $200,000 bill, that is $10,000 per month. Interest accrues separately from the original due date at the variable annual rate under RCW 82.32.050(2).13Washington State Legislature. WAC 458-57-135 – Estate Tax Penalties and Interest Penalties and interest stack, so a six-month delay can push the total owed 30% or more above the original tax. Installment plans are available for estates holding a closely held business.9Washington Department of Revenue. Estate Tax
How Washington and Federal Estate Tax Fit Together
Washington’s tax is entirely separate from the federal estate tax. The federal estate and gift tax exemption for 2026 is $15 million per individual under the One Big Beautiful Bill Act, signed into law on July 4, 2025.14Internal Revenue Service. One, Big, Beautiful Bill Provisions Because the federal threshold is nearly five times Washington’s, many estates owe Washington estate tax but no federal tax at all.
When an estate does owe both, Washington estate tax paid is deductible on the federal return under IRC Section 2058.15Office of the Law Revision Counsel. 26 U.S. Code 2058 – State Death Taxes And although Washington does not allow portability, the surviving spouse can still inherit the deceased spouse’s unused federal exemption by filing a federal estate tax return within nine months of death. Filing to claim federal portability is worth considering even when no federal tax is owed.