Washington · reference

Washington calendar and forms

Every date that matters to a Washington household in the 2027 filing season: the federal calendar, which is the whole income tax calendar, plus the handful of Washington dates that sit beside it, the capital gains return due with the federal one, the Working Families Tax Credit window that opens February 1, the senior exemption deadline of December 31, and the two property tax halves. And the short list of Washington filings an individual actually meets, none of which is an income tax return.

By Charles Trautman, EA, editor

Need to Know Tax · written from Washington State Department of Revenue sources, November 3, 2026; updated November 12, 2026 after the election · not yet reviewed by a Washington practitioner

Washington has no income tax return, so there is no state due date, no state extension and no state estimated payment. The federal Form 1040 is due Thursday, April 15, 2027, the extension runs to Friday, October 15, 2027, and the four federal estimated payments fall on the federal dates. What Washington adds is small and specific. Anyone who owes the capital gains excise tax files a return through My DOR on the same April 15, with the federal return attached, and may have prepaid since October 15, 2026. Anyone who qualifies for the Working Families Tax Credit applies for it separately, in a window that opens February 1, 2027 for the 2026 tax year and stays open about three years. Homeowners 61 and older, or disabled, apply to the county assessor for the property tax exemption by December 31. And the county property tax is paid in two halves, April 30 and October 31, which is what goes on the federal Schedule A.

The forms side is shorter than in any state with an income tax. The Department of Revenue has almost nothing to do with an individual who does not sell investments, run a business or settle an estate. The table lists the filings that come up, in the order a household is likely to meet them.

The 2027 season, dated

Federal and Washington dates for the 2026 return and the 2027 tax year
Date	What happens	Form or filing
Thursday, October 15, 2026	First day the Department accepts prepayment of 2026 capital gains excise tax, six months before the due date. Optional; no quarterly payments are required.	My DOR payment
Saturday, October 31, 2026	Second half of 2026 county property tax due (the first half was due April 30). A payment in 2026 is a 2026 federal deduction.	County tax statement
Tuesday, November 3, 2026	General election. Voters rejected Initiative 645, 57.93% to 42.07%, so the 9.9% tax on income above $1,000,000 enacted under ESSB 6346 stays in law and begins January 1, 2028. Nothing changes on a 2026 return.	Ballot
Thursday, December 31, 2026	Last day of the 2026 tax year: RMDs, charitable gifts, Roth conversions. Deadline to apply to the county assessor for the senior and disabled property tax exemption on taxes collected in 2027, under the wider 2027 income limits; late applications may be accepted. Last day for a Washington charitable gift to count against 2026 capital gains.	County assessor application
Friday, January 15, 2027	Fourth 2026 federal estimated payment due. No state equivalent.	1040-ES
Late January 2027; the IRS announces the date in January	IRS begins accepting 2026 returns. Refunds claiming the earned income credit are held until mid-February.	1040
Monday, February 1, 2027	W-2s and most 1099s due from employers and payers. Working Families Tax Credit window expected to open for tax year 2026, with the 2026 amounts and income limits published; the 2025 window opened February 1, 2026. Prior years back to 2023 can be claimed at the same time.	W-2, 1099; WFTC application
February 2027	County treasurers mail the property tax statements for 2027 collection. Check that a granted senior exemption shows on the statement.	County tax statement
Thursday, April 15, 2027	2026 federal return and balance due; extension request due; first 2027 estimated payment; last day for a 2026 IRA or HSA contribution. Washington capital gains excise tax return and payment due for anyone who owes it, filed through My DOR with the federal return attached; a Washington extension must be requested by this date and requires a federal extension; payment is still due.	1040, 4868, 1040-ES; My DOR capital gains return
Friday, April 30, 2027	First half of 2027 county property tax due; the full year may be paid. Interest and penalty on late payment.	County tax statement
Tuesday, June 15, 2027	Second 2027 federal estimated payment due.	1040-ES
Thursday, July 1, 2027	Deadline to petition the county board of equalization on the 2027 assessed value, or 30 days from the change-of-value notice if later (up to 60 days in counties that have extended it); a denied senior exemption is appealed to the same board.	County BOE petition
Wednesday, September 15, 2027	Third 2027 federal estimated payment due.	1040-ES
Friday, October 15, 2027	Extended 2026 federal return due; extended Washington capital gains return due. Medicare open enrollment begins; 2028 IRMAA will be set from the 2026 return. First day to prepay 2027 capital gains tax.	1040; My DOR
Sunday, October 31, 2027	Second half of 2027 property tax due; the following Monday if the treasurer’s office is closed.	County tax statement
Friday, December 31, 2027	Senior and disabled exemption applications due for taxes collected in 2028.	County assessor application
Monday, December 31, 2029	Last day to apply for the Working Families Tax Credit for tax year 2025. The tax year 2026 window is expected to run about as long.	WFTC application
Washington estate tax returns are due nine months after the date of death, filed with the Department, for gross estates above $3,000,000 (deaths on or after July 1, 2026). Business and occupation tax returns for a sole proprietor run monthly, quarterly or annually on the Department’s schedule, set when the business license is issued.

How the dates fit together

The capital gains return is deliberately tied to the federal return: same due date, same extension, and a copy of the federal return is part of the Washington filing. That means the Washington return cannot be finished before the federal one, and a filer on federal extension is on Washington extension too, with the Washington tax still due April 15. The Department’s advice is to make an estimated payment through My DOR by April 15 when the federal return is not done; paying at least 80% of the final tax by then avoids the substantial underpayment penalty, and paying something avoids the late payment penalty on what was paid. For tax year 2025 the Department moved the date to May 1, 2026 to match IRS storm relief; that was a one-year change.

The Working Families Tax Credit runs on its own calendar because it is not on any return. The application for a tax year opens the February after the year ends, needs the federal return to have been filed first, and stays open for about three years, so the 2025 window runs through December 31, 2029 and a household that never applied can claim 2023, 2024 and 2025 at once in early 2027 alongside 2026. For tax year 2025 the maximums were $335 with no children, $660 with one, $995 with two and $1,330 with three or more, with a $50 minimum, for residents who lived here at least 183 days, were 25 to 64 or had a qualifying child, and qualified for the federal earned income credit or would have but for filing with an ITIN. The 2026 figures are indexed and are published when the window opens. Processing has been running more than 90 days.

The property tax calendar is the one newcomers misread. The assessment year is the year before the taxes are paid: the assessor values the home as of January 1, 2026, sends a change-of-value notice during 2026, and the resulting tax is billed in February 2027 and paid in April and October 2027. The senior exemption follows the assessment year, so an application by December 31, 2026 reduces the bill paid in 2027. For the federal return, the deduction is for the amount paid in the calendar year, so a 2027 Schedule A carries the 2027 payments regardless of which assessment year they relate to.

Worked example: a household with a stock sale on federal extension

A couple sold company stock in 2026 for a $700,000 long-term gain and will file the federal return on extension in October 2027 because a K-1 is late. They estimate the Washington tax in March using the 2025 deduction of $278,000 because the 2026 figure was not yet published when they ran the numbers.

Estimated Washington capital gains tax: ($700,000 − $278,000) × 7%	$29,540
Paid through My DOR by April 15, 2027, with the extension request	$29,540
Final tax when the return is filed October 15, 2027, with the 2026 deduction published at, say, $285,000 (illustrative; the 2026 figure is to come)	$29,050
Refund on the Washington return	$490
Penalty exposure: 80% of final tax is $23,240; the estimate exceeded it	None
Had they paid nothing in April: late payment penalty and interest on $29,050 from April 15, plus the substantial underpayment penalty (verify rates)	Avoidable

The Department matches an unassociated estimated payment and extension to the return when it arrives. The refund requires the return to be filed with the federal return attached; the Department will not refund against an incomplete filing.

The Washington filings a household meets

Washington filings for an individual or household
Filing	What it does	Filed with, and when
Capital gains excise tax return	Reports Washington-allocated long-term capital gains above the standard deduction ($278,000 for 2025; 2026 to come) and computes the 7% and 9.9% tax. No paper form and no form number; only individuals who owe must file. Federal return attached.	Department of Revenue through My DOR or approved software, April 15, 2027; extension by request, payment not extended
Working Families Tax Credit application	Claims the sales tax refund of up to $1,330 (tax year 2025) for households eligible for the federal EITC, including ITIN filers. Not on any return.	Department of Revenue at workingfamiliescredit.wa.gov, by paper, or through tax software; window opens about February 1 after the tax year and stays open about three years
Senior Citizens and People with Disabilities exemption application	Freezes the home’s taxable value and removes the state school levy and excess levies, plus a share of regular levies for the lower income tiers, for owners 61 and older, disabled, or disabled veterans under the county income limit.	County assessor, by December 31 of the assessment year; renewals on the assessor’s schedule
Property tax deferral application	Defers property taxes and special assessments for homeowners 60 and older or retired on disability with income under 90% of county median for 2027, as a lien repaid with interest at sale or death.	County assessor; see the assessor’s deadline
County board of equalization petition	Appeals the assessed value, with comparable sales as of January 1 of the assessment year, or a denied exemption.	County board of equalization, by July 1 or within 30 days of the value notice, whichever is later; up to 60 days where the county has extended it
Washington State Estate and Transfer Tax Return	Required when the gross estate exceeds the filing threshold: $3,076,000 for deaths January 1 to June 30, 2026; $3,000,000 for deaths from July 1, 2026 through 2027. Rates 10% to 20% on the taxable estate for deaths from July 1, 2026.	Department of Revenue, nine months after death
Business license application and excise tax return	Registers a sole proprietor or rental business with the state and reports business and occupation tax on gross receipts and any sales tax collected, including on services taxable since October 1, 2025.	Department of Revenue, before doing business; returns monthly, quarterly or annually as assigned
Use tax	Owed on goods bought without Washington sales tax and used here, including a vehicle brought in by a new resident unless owned long enough before the move; collected by the Department of Licensing when the vehicle is titled, or reported to the Department of Revenue for other purchases.	Department of Licensing at titling; Department of Revenue otherwise
What is missing from the list is the point: there is no Washington income tax return, no withholding form, no extension and no estimated payment voucher for an individual. A Washington household whose software asks for a state return should answer that there is none. The WA Cares and Paid Family and Medical Leave premiums on a pay stub are withheld and remitted by the employer and are never reconciled by the worker.

Filing the federal return from Washington

The federal return is filed from Washington as from anywhere: electronically, through a preparer, commercial software or IRS Free File. The one thing a Washington preparer does that a preparer in an income tax state does not is build the SALT deduction from property tax plus the sales tax election, using the IRS tables at Washington’s high local rates plus the actual tax on a car or other large purchase. With no state income tax to deduct, many Washington households find Schedule A does not beat the standard deduction, $32,200 for a couple in 2026; a year with a large car purchase, a new mortgage or large charitable gifts is the exception.

Federal estimated payments matter more here than in a state with pension withholding, because a Washington retiree’s only withholding is whatever a custodian takes for the IRS. The safe harbors, 100% of last year’s tax or 110% for higher incomes, are in Estimated payments; the simplest Washington fix is federal withholding on a December IRA withdrawal. For a household that owes the capital gains tax, the federal payment on the same gain is usually several times the Washington one and is due on the same schedule.

Behind the scenes: why the capital gains return has no form

The 2021 Legislature told the Department to collect the capital gains tax electronically, and the Department built it into My DOR, the portal businesses already used for excise tax, rather than printing a form. The return is a set of screens that asks for the federal Schedule D figures, the exemptions, the allocation and the deduction, and takes an upload of the federal return. The electronic-only rule, with a waiver only for good cause granted in advance, follows from the small number of filers, 6,726 for tax year 2025, and the size of the payments, more than $1.5 billion. The same logic put the Working Families Tax Credit in its own application rather than on a return: with no income tax return to attach it to, the Department built a stand-alone system and a three-year window, which is why a household can claim several years at once.

The property tax calendar runs a year behind because of how Washington levies: assessors value as of January 1, districts set their levies in the fall against the certified roll, and the treasurer bills the following February. The December 31 exemption deadline is the last day of the assessment year, before the levies are set. A late application is accepted because the statute allows refunds for three years when a qualifying household paid in error, and most assessors would rather grant the exemption than process the refund.

What to bring

County property tax statement and proof of both half-year payments, with dates, for each Washington parcel
Bill of sale for any vehicle, boat or RV bought in 2026, showing the sales tax
Brokerage 1099-Bs and the realized gain report, so the capital gains tax question is settled before April 15
Confirmation of any capital gains prepayment or estimated payment made through My DOR, and your SecureAccess Washington login
Federal estimated payments made in 2026, with dates; there are no state payments to list
1099-Rs and the SSA-1099, with the federal withholding boxes
If you may qualify for the Working Families Tax Credit: proof of 183 days of Washington residence and the filed federal return
For a new resident: the move date and the documents that fix it, in case the former state asks

Questions people ask

Do I file anything with Washington for income tax?

No. There is no individual income tax return, extension or estimated payment. The Washington filings an individual meets are the capital gains excise tax return if you owe it, the Working Families Tax Credit application if you qualify, the senior exemption at the county assessor, and an estate tax return after a death.

When is the Washington capital gains return due?

April 15, 2027, the same day as the federal return, through My DOR with the federal return attached. A federal extension lets you request a Washington extension to October 15, 2027, but the tax is still due April 15; pay an estimate then.

Can I still claim the Working Families Tax Credit for 2024 or 2025?

Yes. Each tax year’s window stays open about three years; 2025 runs through December 31, 2029. File the federal return for that year first if you have not, then apply at workingfamiliescredit.wa.gov, by paper, or through tax software. Up to three prior years can be claimed at once.

I turned 61 this year. Is it too late to apply for the property tax exemption for next year’s bill?

Not until December 31, 2026, and assessors may take late applications after that. Apply with proof of age, ownership and 2026 income; the exemption reduces the taxes collected in 2027, the first year under the wider income limits.

Should I pay my property tax in full in April or in two halves?

Either; there is no discount for paying early. The only tax reason to think about timing is the federal deduction: both halves paid in 2027 go on the 2027 Schedule A, and a household near the line between itemizing and the standard deduction can pay the October half in January instead to bunch two years into one. For most Washington households without a state income tax to deduct, it does not change the result.

One federal return, one April 15, and a December 31 the county assessor cares about

Put April 15 and December 31 on the calendar, apply for the Working Families Tax Credit after the federal return goes in, and if you sold stock this year, settle the capital gains question before the deadline, not after.

Written by Charles Trautman, EA, editor  ·  Need to Know Tax, Lone Tree, Colorado
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Updated November 12, 2026, after the November 3 election · tax year 2026 figures · awaiting review by a Washington practitioner — use the right article