Roth Conversions in Retirement: A Guide for Boise and Treasure Valley Retirees

If you're retired or approaching retirement in the Treasure Valley, you've likely heard the phrase "Roth conversion" from a friend, a webinar, or your own research. It's one of the more talked-about retirement tax strategies, and for good reason: done at the right time, it can meaningfully change how much of your savings you keep versus send to the IRS over your lifetime. Done at the wrong time, it can create a tax bill you didn't need to pay. Here's what a conversion actually does, why Boise-area retirees look at them, and the factors worth weighing before you convert a dollar.

What a Roth Conversion Actually Does

A Roth conversion moves money from a traditional IRA (or an old 401(k) you've rolled into one) into a Roth IRA. The amount you convert counts as ordinary income in the year you convert it, so you owe tax on it now, at your current federal and Idaho rates. In exchange, that money then grows tax-free, and qualified withdrawals in retirement come out tax-free too. You're not eliminating the tax bill; you're choosing to pay it now instead of later, in the hope that "now" is a cheaper time to pay it than "later" would be.

That trade only makes sense if you have a reasonable view of what your tax picture looks like today versus down the road. That's the whole exercise.

Why Treasure Valley Retirees Look at Conversions

Three situations come up often in the Boise, Meridian, and Eagle area:

• A gap year (or several) between when you stop working and when Social Security or pension income starts, when your taxable income is temporarily lower than it will be later.
• A desire to reduce future required minimum distributions (RMDs), since money that's already in a Roth isn't part of that calculation.
• Legacy planning, since heirs who inherit a Roth IRA receive tax-free distributions, while heirs of a traditional IRA owe income tax on what they withdraw.

None of these make a conversion automatically right for you. They're simply the situations where it's worth doing the math.

Idaho's Flat Tax Simplifies (Some of) the Math

One thing that makes conversion math a little more straightforward for Idaho residents than for retirees in many other states: Idaho taxes personal income at a flat rate rather than a bracket structure. The rate for 2025 is5.3% on Idaho taxable income; the Tax Foundation's state tax data (taxfoundation.org/location/idaho) confirms the same flat 5.30% rate carrying into 2026. A converted dollar is taxed the same whether it's your first dollar of Idaho income for the year or your two-hundred-thousandth; there's no separate state bracket to "fill up" the way there is federally.

That doesn't make the decision simple, it just removes one layer of complexity. The federal side still has brackets, and converting enough in one year can push you from one federal bracket into the next, or trigger higher Medicare premium tiers two years later if you're on Medicare. The size and timing of a conversion still matter enormously; Idaho's flat rate just means you don't also have to model a state bracket on top of the federal one.

A Hypothetical Example: Filling a Lower Bracket in a Quiet Income Year

Consider a hypothetical example. A couple in Meridian retires at 63. Their only income for the next few years is modest investment income; Social Security won't start until 67, and neither has begun taking RMDs. Rather than let those years pass with unusually low taxable income, they convert a portion of a traditional IRA each year, deliberately sized to use up the lower federal brackets before jumping into a higher one. Each year's conversion is taxed at a comparatively low federal rate, plus Idaho's flat 5.3%, and the converted amount then grows tax-free going forward.

Contrast that with converting the same total amount all at once, or waiting until RMDs and Social Security are already stacking up their income, when the same dollars would likely be taxed at a meaningfully higher rate. The strategy isn't "convert everything" or "convert nothing"; it's sizing each year's conversion to the space available in that year's income picture. This example is illustrative only; the right amount for you depends on your own income, deductions, and timeline.

RMDs, the Five-Year Rule, and Why Timing Matters

Two rules shape when a conversion tends to make the most sense.

Original owners of Roth IRAs never have to take RMDs during their lifetime, unlike traditional IRAs, per aCongressional Research Service summary of RMD rules. Traditional IRA owners generally must begin RMDs at age 73 if born between 1951 and 1958, and at age 75 if born in 1960 or later (those born in 1959 are treated as subject to age 73 under the IRS's final regulations, per the same CRS summary).

Converted funds also have their own five-year clock: each conversion needs to season for five years (and you generally need to be 59½) before its earnings can be withdrawn tax- and penalty-free. Converting well before you plan to need the money avoids running into that clock later.

Put together, converting in the years before RMDs begin, rather than waiting, tends to give a conversion the most room to work in your favor.

What to Weigh Before You Convert

A conversion isn't free money moved to a better account; it has real costs to weigh against the benefit:

• The tax bill is due the year you convert, generally from funds outside the IRA if you want the full converted amount to keep growing tax-free.
• A large conversion can temporarily raise your income enough to affect Medicare premium surcharges two years later, or reduce eligibility for certain income-based credits in the conversion year.
• If you expect your tax rate to be lower in retirement than it is today, converting may work against you rather than for you.

None of these rule out a conversion; they're simply the reasons the "how much, and in which years" questions matter more than the yes-or-no question.

Is a Roth Conversion Right for You?

The honest answer is that it depends on your specific income timeline, your other assets, and what you're trying to accomplish, whether that's lower lifetime taxes, a cleaner legacy for your heirs, or simply more flexibility in retirement. A conversion strategy built around your actual numbers looks very different from a generic rule of thumb.

Talk with a Boise-based advisor about whether a Roth conversion fits your retirement plan.