Washington’s 9.9% income tax takes effect January 1, 2028, and it has produced a fair amount of urgency about converting traditional IRA balances to Roth before the deadline arrives. For most people, that urgency is misplaced.
Washington’s tax applies to household income above a $1,000,000 standard deduction. A Roth conversion is one of the few large income events you control completely — you choose the amount, and you choose the year. Conversions sized the way conventional planning recommends, filling the lower federal brackets rather than the top one, land far below $1,000,000 in any single year. Spread across several years, a substantial balance converts without Washington’s tax ever applying, before 2028 or after it.
The 2028 date matters in one situation: your balance is large enough that no workable schedule keeps annual conversions under the threshold. This post covers the mechanics, the arithmetic, and that narrow case.
This post is part of our Complete Guide to Washington’s New Income Tax.
How a conversion enters the Washington base
A Roth conversion moves money from a traditional IRA or other pre-tax account into a Roth. You pay income tax on the converted amount in the year of conversion; the money then grows tax-free, and qualified distributions are not subject to income tax.
The converted amount is included in your federal adjusted gross income in the year of conversion. Beginning January 1, 2028, Washington imposes a 9.9% tax on Washington taxable income, which is computed from federal AGI with statutory modifications and then reduced by the Washington standard deduction of $1,000,000. So a conversion reaches the Washington base the same way any other ordinary income does — through federal AGI.
Two points follow. Washington’s existing capital gains tax does not apply to conversions, because a conversion generates ordinary income rather than long-term capital gain. And until January 1, 2028, Washington has no tax on this income at all — a conversion done in 2026 or 2027 carries federal tax only.
The threshold is annual, which means it can be laddered
The $1,000,000 standard deduction applies per year, not per conversion. That makes Washington’s tax straightforward to avoid: convert less than the threshold in any single year. Take a $3 million traditional IRA and $500,000 of other annual income.
| Convert all at once | $500,000/year for six years | |
|---|---|---|
| AGI in a conversion year | $3,500,000 | $1,000,000 |
| Less Washington standard deduction | $1,000,000 | $1,000,000 |
| Washington taxable income | $2,500,000 | $0 |
| Washington tax at 9.9% | $247,500 | $0 |
The same $3 million converts either way. The laddered path pays no Washington tax in any year, before or after 2028, because no single year clears the deduction. There is no deadline to beat.
This is also how conventional Roth planning says to do it, for reasons that have nothing to do with Washington. Spreading conversions keeps more of each year’s conversion in lower federal brackets. A lump conversion buries most of the balance at the top rate — 37% for joint filers on taxable income above $768,700 in 2026. On these facts the ladder wins on the Washington tax outright, and for someone with lower current income it wins substantially on federal tax as well.
When the 2028 date actually binds
The pre-2028 window changes the answer for one profile: a pre-tax balance large enough that no sensible schedule keeps annual conversions under $1,000,000 before the tax arrives. With a $3 million balance and two years left, that is not you. With $15 million and a reason to finish quickly, it might be.
What makes that profile coherent rather than arbitrary is that the same facts drive three conclusions at once.
A balance that large produces required minimum distributions that keep you in the top federal bracket for life. RMDs begin at age 73, or 75 for those born in 1960 or later, and are included in federal AGI. If your rate never improves, waiting for a lower-bracket year buys you nothing — there are no gap years.
That same balance keeps you in the top Medicare IRMAA tier permanently. IRMAA reaches its highest tier at $500,000 of MAGI for individuals and $750,000 for joint filers, and those figures are frozen by statute through at least 2028 while the lower tiers index annually. Qualified Roth distributions are excluded from gross income, so they never enter AGI and never enter IRMAA MAGI. Converting removes that money from the surcharge calculation permanently. Roth IRAs also have no required minimum distributions during the owner’s lifetime.
And that same balance is what makes laddering under Washington’s threshold impossible before 2028.
So for this profile, converting early is defensible on its own merits, and Washington’s deadline is a reason to do it sooner rather than later. For everyone else, Washington’s tax is not the binding constraint — the federal bracket is.
One timing note if IRMAA is part of your analysis: the relevant age is 63, not your retirement date. IRMAA uses a two-year lookback, so a conversion at 63 sets your premiums at 65. A conversion at 62 or earlier has no IRMAA consequence at all, whatever its size.
Two things that could change the answer
The tax could be repealed or struck down. Initiative 645 is certified for the November 3, 2026 ballot and would repeal the tax before it takes effect, and a constitutional challenge is pending. But the tax remains law, effective January 1, 2028, unless voters repeal it or the courts strike it down — plan as though it arrives on schedule.
You cannot undo a conversion. The ability to recharacterize was eliminated by the Tax Cuts and Jobs Act in 2018. Model the federal cost before you convert, and plan to pay that tax from non-retirement assets.
What to do
If you are a Washington resident weighing a conversion, the Washington question is narrow and usually answerable in one step: would the conversion, plus your other income, push a single year above $1,000,000? If not, Washington’s tax is not a factor and the decision is a federal one for your CPA and financial advisor. If yes, the question becomes whether a multi-year schedule solves it — and if it cannot, whether completing conversions before December 31, 2027 is worth doing.
For more on retirement income and Washington’s tax, see our Washington State Taxes guide. If you have nonqualified deferred compensation, see Deferred Compensation and Washington’s 9.9% Income Tax — distribution schedules are far less flexible than conversion timing, which is why that planning is more urgent than this one.
Frequently asked questions
Does the Roth conversion window really close in 2028?
No. Conversions remain available indefinitely, and Washington’s tax only reaches a conversion that pushes your Washington taxable income above the $1,000,000 standard deduction in a single year. Conversions sized below that threshold are unaffected by the 2028 date.
Will Washington tax my Roth conversion?
Not before 2028. From January 1, 2028, a conversion is included in federal AGI, which is the base for Washington’s income tax — so a conversion that takes your Washington taxable income above the $1,000,000 deduction would incur the 9.9% tax, unless voters repeal it through Initiative 645 on the November 3, 2026 ballot or the courts strike it down in the pending constitutional challenge.
Can I avoid Washington’s tax by converting over several years?
Generally yes. The $1,000,000 standard deduction applies annually, so conversions kept below the threshold in each year face no Washington tax regardless of when they occur.
Can I undo a Roth conversion?
No. Recharacterization was eliminated by the Tax Cuts and Jobs Act in 2018.
This post is for informational purposes only and does not constitute legal or tax advice. Consult a qualified tax professional regarding your specific circumstances.
Thinking about converting before 2028?
Washington’s income tax changes the timing analysis for some conversions and not others. Joe Wallin is a startup and tax attorney with 25+ years of experience advising founders and high earners. Book a 20-minute call to talk through where yours falls.
Book a Free 20-Minute Call →Want the full playbook first? The Washington State Tax Planning Guide covers Roth timing, QSBS, and domicile strategy — $49.99.
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