How Roth Conversions Can Reduce Your Future IRMAA Costs

Roth conversions and IRMAA are two of the most important topics in retirement tax planning — and they're deeply connected. Converting too much in one year can trigger IRMAA surcharges. But done strategically over time, Roth conversions can dramatically reduce your lifetime IRMAA costs by lowering the Required Minimum Distributions that drive up your income in later years.

The Problem: RMDs Push You Into IRMAA

Starting at age 73, you're required to take minimum distributions from traditional IRAs and 401(k)s. These RMDs are calculated as a percentage of your account balance, and that percentage increases every year as you age.

Here's the challenge: if your traditional IRA has grown substantially, your RMDs alone can push you over an IRMAA threshold — and there's nothing you can do about it. RMDs are mandatory.

Example: A couple with $2 million in combined traditional IRAs at age 73:

• First-year RMD: approximately $75,500
• Social Security: $50,000
• Investment income: $15,000
• Total MAGI: ~$140,500

By age 80, with continued growth and increasing RMD percentages, MAGI could easily exceed $222,000 (joint IRMAA threshold), triggering $2,500+/year in surcharges — even without any discretionary withdrawals.

The Solution: Roth Conversions Shrink Future RMDs

Every dollar you convert from a traditional IRA to a Roth IRA reduces your traditional IRA balance. A smaller balance means smaller RMDs. And Roth withdrawals don't count toward MAGI at all.

The Math in Action

Without Roth conversions:

• Traditional IRA at 73: $2,000,000
• RMD at 73: ~$75,500
• RMD at 80: ~$105,000 (higher percentage, continued growth)
• MAGI at 80: $170,000+ (likely in IRMAA Tier 2 or higher)

With $80,000/year Roth conversions from ages 63-72:

• Total converted: $800,000 (now in Roth, growing tax-free)
• Traditional IRA at 73: ~$1,200,000 (reduced balance)
• RMD at 73: ~$45,300
• RMD at 80: ~$63,000
• MAGI at 80: $128,000 (well below IRMAA threshold)
• IRMAA savings: $2,500+/year for potentially 20+ years = $50,000+

The Optimal Roth Conversion Window for IRMAA Reduction

The best time for IRMAA-focused conversions depends on your situation:

Before Age 63 (Best Case)

Conversions before age 63 don't affect IRMAA at all, because:

• Medicare starts at 65
• IRMAA uses a two-year lookback
• Income at age 62 affects IRMAA at age 64 — but you're not on Medicare yet at 64
• Income at age 63 affects IRMAA at age 65 — your first Medicare year

This makes ages 59½-62 the absolute sweet spot: no early withdrawal penalties, no IRMAA impact, often lower income (if retired), and no RMDs competing for tax bracket space.

Ages 63-72 (IRMAA-Aware Conversions)

After age 63, conversions affect IRMAA two years later. You can still convert — just size conversions to stay below IRMAA thresholds:

1. Calculate your base MAGI (Social Security + pension + investment income)
2. Find the gap between base MAGI and the next IRMAA threshold
3. Convert up to that gap amount — no more

Ages 73+ (After RMDs Begin)

Conversions are still possible but less efficient because you must take your RMD first (RMDs can't be converted). However, if RMDs already push you into an IRMAA tier, you might consider converting more in that year — since you're already paying the IRMAA surcharge, additional conversion income in the same tier costs nothing extra in IRMAA.

Strategy: The IRMAA-Optimized Conversion Plan

Here's a framework for planning conversions with IRMAA in mind:

Step 1: Know Your IRMAA Thresholds

For married filing jointly (projected 2027): $222,000 / $280,000 / $350,000 / $420,000 / $750,000. Identify which threshold is closest to your projected MAGI.

Step 2: Calculate Your "Conversion Budget"

Take the IRMAA threshold and subtract your base MAGI. That's your conversion budget — the maximum you can convert without triggering a higher IRMAA tier.

Example: Base MAGI of $180,000 with a threshold of $222,000 = $42,000 conversion budget.

Step 3: Evaluate Whether Crossing the Cliff Is Worth It

Sometimes it makes sense to exceed the threshold — especially if you can convert a large amount for a relatively small IRMAA cost. Going from $222,000 to $260,000 triggers approximately $2,500 in IRMAA but converts $80,000 to Roth, saving potentially $10,000+ in future taxes and IRMAA combined.

Step 4: Consider Alternating Years

An advanced strategy: do a large conversion in one year (accepting the IRMAA hit two years later) and then do no conversion the next year (staying below IRMAA). This can be more efficient than moderate conversions every year that always trigger IRMAA.

Real-World Example: 10-Year IRMAA Savings

Tom and Sarah: Both 62, retiring this year. $1.8M in traditional IRAs, $45,000/year Social Security starting at 67.

No conversions:

• Traditional IRA grows to ~$2.5M by age 73
• RMDs at 73: ~$94,000
• MAGI at 73: ~$155,000 (with SS)
• By 80, RMDs push MAGI above $222,000 threshold
• IRMAA cost (ages 80-95): approximately $37,500

With $90,000/year conversions (ages 62-72):

• Total converted: $990,000
• Traditional IRA at 73: ~$1.1M
• RMDs at 73: ~$41,500
• MAGI stays below IRMAA threshold through age 95
• IRMAA cost: $0
• IRMAA savings: $37,500
• Plus income tax savings on smaller RMDs: $60,000+

Using Bullseye to Model Roth Conversions and IRMAA

Bullseye is built to help you optimize this exact trade-off:

• Year-by-year IRMAA projections: See your projected MAGI and resulting IRMAA surcharges for every year of retirement
• RMD forecasting: See how your traditional IRA balance drives RMDs and how conversions reduce them
• Scenario comparison: Use the Scenarios feature to compare "no conversions" vs. "$50K/year" vs. "$100K/year" — see the lifetime difference in IRMAA, taxes, and total wealth
• Tax bracket visibility: Identify the optimal conversion amount that fills up your current tax bracket without crossing into the next