When Roth conversions make sense:

• You're in a lower tax bracket now than you expect to be when RMDs begin
• You have a large pre-tax balance that will generate significant forced income at age 73+
• You want to reduce future RMD amounts and the Medicare IRMAA exposure that comes with them
• You have a surviving spouse who will eventually file as a single taxpayer (brackets compress significantly)
• You want to leave tax-free assets to heirs rather than a taxable IRA

The conversion window most people miss:

The years between retirement and age 73 — when RMDs haven't started and Social Security may still be deferred — often represent the lowest taxable income of your retirement. This is the optimal window to convert at the lowest possible rate. Once RMDs begin, your taxable income floor rises and the window narrows.

Arizona-specific note:

Arizona does not tax Social Security benefits and follows federal treatment on most retirement income. Roth IRA withdrawals are not taxable at the state level. This means every dollar converted and moved to Roth saves you Arizona income tax on future withdrawals as well.

What to watch:

Converting too much in a single year can push you into the next IRMAA tier two years later, increase the taxable portion of your Social Security, and spike your state tax liability. The right conversion amount is the result of modeling — not a rule of thumb.

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Why RMDs create tax problems:

• RMDs layer on top of Social Security, pensions, and other income — pushing effective tax rates higher than most retirees expect
• Large pre-tax balances grow over time, meaning RMD amounts increase year over year even if you spend less
• Missing an RMD triggers a 25% excise tax on the shortfall (reduced from 50% under SECURE 2.0, but still severe)
• Delaying your first RMD to April 1 of the following year forces two RMDs in one year — a common and expensive mistake

Strategies to reduce RMD impact:

• Roth conversions before age 73 — reduce the pre-tax balance that generates future RMDs
• Qualified Charitable Distributions (QCDs) — if you're 70½ or older, donate up to $105,000/year directly from your IRA to charity; satisfies the RMD requirement without increasing taxable income or MAGI
• Strategic withdrawal sequencing — drawing from pre-tax accounts early in retirement, before RMDs are mandatory, can reduce the balance and future forced distributions
• Coordinating with Social Security timing — delaying Social Security while drawing from IRAs is sometimes the right sequence; sometimes it isn't; it depends on your specific numbers

SECURE 2.0 changes affecting Arizona retirees:

The SECURE 2.0 Act pushed the RMD starting age to 73 and eliminated pre-death RMDs from Roth accounts inside employer plans. Catch-up contribution rules for high earners also changed. These updates affect how much you'll have in pre-tax accounts at RMD start and the strategy around converting before then.

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How IRMAA works:

• The 2026 standard Part B premium is $185.00/month per person
• IRMAA surcharges begin at $106,000 MAGI for single filers and $212,000 for married filing jointly
• Surcharges are "cliff-based" — one dollar over a tier threshold moves you into the full next tier
• A married couple at IRMAA Tier 3 pays over $9,000/year in combined Part B and Part D surcharges above the standard premium
• Medicare uses your tax return from two years prior — your 2024 return determines 2026 premiums

What triggers IRMAA spikes:

• A large Roth conversion in a single year
• RMDs beginning or increasing
• Selling a rental property or business
• A large capital gain distribution from a mutual fund
• Two RMDs in one year (from delaying the first)
• Death of a spouse (surviving spouse files single — brackets compress significantly)

How to manage IRMAA exposure:

• Model conversions against IRMAA tiers, not just income tax brackets
• Use QCDs to satisfy RMDs without adding to MAGI
• Space large income events across multiple years when possible
• If a one-time income spike pushes you into IRMAA, file Form SSA-44 to request a reduction based on the life-changing event
• Plan large transactions (property sales, lump-sum distributions) with the two-year lookback in mind

Arizona-specific note:

Arizona does not tax Social Security benefits and has a flat 2.5% state income tax rate as of 2023. While IRMAA is a federal calculation, state tax planning affects your overall income picture and the cost-benefit of strategies designed to reduce MAGI.

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Federal taxation thresholds:

• 0% of Social Security is taxable if combined income is below $25,000 (single) / $32,000 (MFJ)
• Up to 50% is taxable between $25,000–$34,000 (single) / $32,000–$44,000 (MFJ)
• Up to 85% is taxable above $34,000 (single) / $44,000 (MFJ)
• These thresholds have never been adjusted for inflation — almost all retirees with IRA distributions, pensions, or investment income will hit the 85% level

How IRA withdrawals and RMDs affect Social Security taxation:

Every dollar of IRA distribution or RMD increases your combined income — which in turn increases the taxable portion of your Social Security benefit. This creates a "tax torpedo": a window where the effective marginal tax rate is higher than your stated bracket, because each additional dollar of income is taxing two income sources simultaneously.

Strategies:

• Build a withdrawal sequencing plan that manages combined income deliberately
• Use Roth conversions in lower-income years to reduce future IRA distributions that would spike combined income
• Delay Social Security if your income in early retirement can be funded from other sources — this both increases your eventual benefit and gives you more time to reduce pre-tax balances
• Consider QCDs to satisfy RMDs without adding to combined income

Arizona note:

Because Arizona doesn't tax Social Security, the state-level concern is more limited. The federal interaction between RMDs, investment income, and Social Security is where the planning work is concentrated for Arizona retirees.

Relevant tools:

Related reading

The three account buckets:

• Pre-tax (taxable on withdrawal): Traditional IRA, 401(k), 403(b), SEP-IRA — every dollar withdrawn is ordinary income
• After-tax (taxable on gains only): Brokerage accounts — principal is not taxed again; growth is subject to capital gains rates
• Tax-free: Roth IRA, Roth 401(k) — qualified withdrawals are entirely tax-free and do not count toward MAGI

The conventional rule — and why it's often wrong:

The standard advice is taxable → pre-tax → Roth. The logic: let tax-free money grow longest. But this ignores bracket management, IRMAA exposure, and the reality that deferring all pre-tax withdrawals until RMDs begin can create a forced income spike at 73+ that's worse than drawing down strategically earlier.

A better framework:

• In early retirement (pre-RMD), model how much pre-tax income you can take while staying in your target bracket — and potentially convert the rest to Roth
• Use after-tax accounts tactically to fill income needs without adding ordinary income
• Reserve Roth for years when income spikes are unavoidable (property sales, large one-time expenses) and for legacy planning
• Always plan around the two-year IRMAA lookback — what you do this year affects Medicare costs in two years

What good sequencing requires:

A multi-year projection that accounts for Social Security timing, RMD start date, IRMAA tiers, Arizona state tax, beneficiary considerations, and your actual spending needs. This is not a spreadsheet calculation — it requires judgment about what's changing and when.

Relevant tools:

Related reading