A Roth conversion before age 63 is the last conversion that will not raise your future Medicare premiums, because Medicare’s income-related monthly adjustment amount (IRMAA) looks back two years at your income and Part B usually begins at 65. Many pre-retirees hear “63 is a deadline” without being told why, and the why is a single timing mechanic worth understanding before the window closes.
Because IRMAA uses a two-year income lookback and Medicare Part B typically starts at 65, the tax year you turn 63 is the first year a Roth conversion can raise a future Medicare premium. Converting before 63 avoids IRMAA entirely. Converting at 63 or later can lock in surcharges that, for a couple with both spouses enrolled, run from roughly $2,297 to about $13,872 per year in combined Part B and Part D costs.
What does the IRMAA two-year lookback actually mean?
IRMAA is a Medicare surcharge added to Part B and Part D for higher-income enrollees, and it is set from your modified adjusted gross income (MAGI) two years earlier. Your 2026 premium is calculated from your 2024 tax return. Because a Roth conversion is fully taxable ordinary income that raises MAGI in the year you convert, a conversion two years before a Medicare year can push you into a higher premium tier.
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How is my 2026 Medicare premium set from my 2024 tax return?
Your 2026 Medicare premium is set from your 2024 tax return because SSA uses the most recent return the IRS has on file, which is almost always two years old. MAGI equals your adjusted gross income plus tax-exempt interest, so a conversion done in 2024 raises the income figure SSA reads for your 2026 Part B and Part D premiums.
The Social Security Administration (SSA) receives your MAGI from the IRS and uses the most recent return on file, which is almost always two years prior. For 2026 premiums, that means your 2024 MAGI. MAGI here is your adjusted gross income plus any tax-exempt interest. A Roth conversion adds to AGI dollar for dollar, so a $150,000 conversion in 2024 shows up in the income figure SSA reads for your 2026 Part B and Part D premiums.
Why does that make the year I turn 63 the trigger year?
Part B usually begins the month you turn 65, so working backward two years, income from the year you turn 63 is the first that lands on a Medicare-premium year. Income earned at 62 or earlier is read only for years before you enroll, so it never touches a premium. That makes 63 the first conversion year that can raise a surcharge.
Part B typically begins the month you turn 65. Working backward two years, the income from the year you turn 63 is the first income that lands on a Medicare-premium year (age 65). Income at 62 or earlier is read only for years before you are enrolled, so it never touches a premium. That is why the last conversion year that cannot raise a Medicare premium is the year you turn 62, and the year you turn 63 is the first that can.
Is age 63 a one-time deadline or does every year after count?
Age 63 is not a single cliff after which conversions are safe again. IRMAA is re-assessed every year, so income at 63 sets your age-65 premium, income at 64 sets age-66, income at 65 sets age-67, and so on. Age 63 is simply the first tax year whose income reaches a Medicare year. Every year afterward also counts, which is the part most explanations leave out.
How income at 63, 64, and 65 each feeds a different Medicare year
The two-year lookback is a rolling chain rather than a one-time gate. Each income year maps to a Medicare year two years later, so income at 63 sets your age-65 premium, income at 64 sets age-66, and income at 65 sets age-67. Converting freely at 64 or 65 can re-create the same surcharge you avoided by waiting past 63.
The two-year lookback is a rolling chain, not a one-time gate. Each year of income maps to a Medicare year two years later, so treating 63 as a single deadline and then converting freely at 64 or 65 can re-create the exact surcharge you were trying to avoid.
| Income year (your age) | Medicare premium year it sets | Can a conversion affect IRMAA? |
|---|---|---|
| Age 62 | Age 64 (before Part B) | No |
| Age 63 | Age 65 (Part B starts) | Yes, first year that counts |
| Age 64 | Age 66 | Yes |
| Age 65 | Age 67 | Yes |
What if I delay Medicare past 65, does the deadline move?
Yes. The cutoff is anchored to your actual Part B start date, not a fixed birthday. If you keep working past 65 with creditable employer coverage and delay Part B, the two-year lookback slides with you, and your first income year that affects a premium becomes two years before your real enrollment. Someone enrolling at 68 has a first-affected income year at 66.
The cutoff is anchored to your actual Part B start date, not a fixed birthday. If you keep working past 65 with creditable employer coverage and delay Part B, the two-year lookback slides with you. Your first income year that affects a premium becomes two years before your real enrollment date. Someone enrolling at 68 has a first-affected income year at age 66, not 63. The number moves with your enrollment, so confirm your own start date before you assume “63.”
How much do Roth conversions after 63 cost in IRMAA?
In 2026 the standard Part B premium is $202.90 per person per month, and IRMAA begins above $109,000 MAGI for single filers and $218,000 for married couples filing jointly. Surcharges climb across five tiers. For a couple with both spouses enrolled, the combined Part B and Part D IRMAA runs from roughly $2,297 per year at the first tier to about $13,872 per year at the top.
2026 IRMAA thresholds and surcharges for couples and singles
The table below shows the 2026 IRMAA tiers, which are set from 2024 MAGI. The surcharge column reflects the combined Part B and Part D IRMAA for a married couple with both spouses enrolled in Medicare. Because IRMAA is charged per enrolled person, a couple generally pays roughly double a single enrollee’s surcharge at the same income tier.
The table below shows 2026 IRMAA tiers, which are based on 2024 MAGI. The surcharge amounts are the combined Part B and Part D IRMAA for a married couple with both spouses enrolled in Medicare. IRMAA is charged per enrolled person, so a couple pays roughly double a single person’s surcharge.
| 2024 MAGI (married filing jointly) | 2024 MAGI (single) | Approx. 2026 IRMAA per couple, per year (Part B + Part D) |
|---|---|---|
| Up to $218,000 | Up to $109,000 | $0 (standard $202.90/month each) |
| $218,001 to $274,000 | $109,001 to $137,000 | ~$2,297 |
| $274,001 to $342,000 | $137,001 to $171,000 | ~$5,770 |
| $342,001 to $410,000 | $171,001 to $205,000 | ~$9,240 |
| $410,001 to $749,999 | $205,001 to $499,999 | ~$12,710 |
| $750,000 or more | $500,000 or more | ~$13,872 (top tier) |
Why IRMAA is a cliff, not a phase-in, the one-dollar-over problem for both spouses
IRMAA is a cliff, not a phase-in. One dollar of MAGI over a threshold triggers the entire tier for both spouses’ Part B and Part D, not a gradual charge on the amount above the line. A couple at $217,999 pays the standard premium; at $218,001 they pay roughly $2,297 more for the year, so buffer room below a tier can matter.
Because the surcharge applies to the whole tier rather than the amount above the line, the last two dollars of a conversion can carry an effective cost of thousands of dollars. Near a threshold, the marginal cost of the final dollars converted can run into the hundreds of percent, which is why leaving buffer room below a tier is often worth more than the last few dollars converted.
How much can I convert before 63 without triggering IRMAA?
In the years before you turn 63, a Roth conversion cannot raise a Medicare premium, so IRMAA thresholds do not constrain how much you convert. The only ceiling in that window is your income-tax bracket. Many pre-retirees use the gap between 59 and a half (penalty-free withdrawals) and 62 to front-load conversions up through the 22% or 24% bracket while IRMAA is not yet a factor.
The 59-and-a-half to 63 IRMAA-free window explained
The years from 59 and a half through the year you turn 62 are often called the Medicare gap years or the IRMAA-free window. Withdrawals and conversions are penalty-free after 59 and a half, and IRMAA does not read that income because it falls two years before any Part B year. Low MAGI in these years can leave room to convert at favorable rates.
For a couple who has stopped working but not yet claimed Social Security, MAGI in these years can be unusually low, leaving room to convert at favorable rates. Our guide on how much to convert walks through sizing each year’s conversion.
A worked example: front-loading a seven-figure balance inside the 22% or 24% bracket
Consider a married couple, both 61, with a large traditional IRA and little other income during their gap years. In 2026 their standard deduction is $32,200, and the 24% bracket runs to $403,550 of taxable income. A $200,000 conversion nets about $167,800 of taxable income, inside the 24% bracket, and because they convert before 63, none of it touches a Medicare premium.
Consider a married couple, both 61, with a $2.4 million traditional IRA and little other income during their gap years. In 2026 the standard deduction for a couple filing jointly is $32,200, the 22% bracket runs to $100,800 of taxable income, and the 24% bracket runs to $403,550. Suppose they convert $200,000 in the year they are 61. After the $32,200 deduction, taxable income is about $167,800, which sits inside the 24% bracket. Because they are converting before 63, none of it touches a Medicare premium.
Repeating a similar conversion at ages 60, 61, and 62 could move roughly $600,000 into the Roth over three years with no IRMAA impact. Contrast that with the same $200,000 conversion at age 63 alongside $30,000 of other income: MAGI reaches $230,000, above the $218,000 tier-one threshold, which can add roughly $2,297 to the couple’s combined Part B and Part D cost two years later. The dollars converted are identical; the timing is what adds or avoids the surcharge. Figures illustrate the mechanic and are not a projection.
What happens if I skip the window? The do-nothing cost
Skipping the pre-63 window does not make the tax disappear; it defers and often enlarges it. A seven-figure pre-tax balance keeps compounding, and required minimum distributions (RMDs) beginning at 73 (or 75 for those born in 1960 or later) can force large taxable withdrawals into the 32% bracket. Those RMDs also raise MAGI, which can push IRMAA higher in the same years, and a surviving spouse faces compressed single brackets.
RMDs at 73, and the survivor “widow’s penalty”
Under current rules, RMDs begin at age 73, rising to 75 for anyone born in 1960 or later, with the earliest age-75 RMD year being 2035. You cannot convert an RMD, so bracket flexibility shrinks once distributions start. When one spouse dies, the survivor files as single, where the same income meets narrower brackets and a lower IRMAA threshold of $109,000.
An unconverted seven-figure IRA can generate six-figure RMDs that stack on Social Security and pensions, often landing in the 32% bracket and lifting MAGI into higher IRMAA tiers at once. Because you cannot convert an RMD, bracket flexibility shrinks once RMDs start. There is also the survivor issue: when one spouse dies, the survivor files as single, where the same income hits narrower brackets and a lower IRMAA threshold ($109,000 rather than $218,000). This single-bracket compression is often called the widow’s penalty. Our 2026 RMD overview covers the timing.
What should I do before I turn 63?
Before the year you turn 63, many pre-retirees confirm their real Part B start date, estimate MAGI for each gap year, and size conversions to a target tax bracket while IRMAA is not yet a constraint. Ages 60 through 63 also open a larger catch-up window, and in some cases paying IRMAA on purpose can still be the better long-run choice. A conversion is irreversible and must be completed by December 31.
- Confirm your real Part B start date, since the two-year lookback is anchored to enrollment rather than a fixed birthday.
- Estimate your MAGI in each gap year, including any other income you expect to report.
- Size each year’s conversion to a target tax bracket while IRMAA is not yet a constraint.
Coordinate the SECURE 2.0 super catch-up (ages 60 to 63) with your conversions
SECURE 2.0 created a higher super catch-up for workplace plans at ages 60 through 63, allowing an extra $11,250 in 2026 on top of the regular limits. That window overlaps almost exactly with the pre-Medicare conversion window, so someone still working can pair larger 401(k) contributions with Roth conversions in the same low-income years rather than treating them as separate steps.
The super catch-up window overlaps almost exactly with the pre-Medicare conversion window, so the two can be treated as one coordinated 60-to-63 play rather than two separate tips. Watch the 3.8% net investment income tax above $250,000 MAGI for couples; a conversion is not itself investment income, but it can raise MAGI enough to expose other income to the tax.
When paying IRMAA on purpose still makes sense, and filing Form SSA-44
Accepting an IRMAA surcharge can still be the better choice when converting at 63 or later avoids a much larger future tax bill from RMDs. The surcharge is a known annual cost weighed against years of tax-free Roth growth. If income drops from a life-changing event, you can file Form SSA-44, but a voluntary conversion does not qualify, so it will not undo the surcharge.
The surcharge is a known annual cost that can be weighed against decades of tax-free Roth growth. Separately, if your income drops because of a life-changing event such as retirement, marriage, or the death of a spouse, you can ask SSA to use more recent income by filing Form SSA-44. A voluntary Roth conversion is not a qualifying life-changing event, so SSA-44 will not undo a surcharge caused by a conversion; our IRMAA appeal guide explains what does qualify.
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Q3 Advisors is a registered investment adviser focused on retirement tax planning. This page is educational and is not advice; consult a qualified professional.
Frequently asked questions
Does a Roth conversion count as income for IRMAA?
Yes. A Roth conversion is fully taxable ordinary income in the year you convert, and it raises your adjusted gross income dollar for dollar. Because IRMAA is based on modified adjusted gross income (AGI plus tax-exempt interest), a conversion increases the MAGI that Medicare reads two years later. A large conversion can push you into a higher Part B and Part D premium tier.
How does the two-year lookback rule work for IRMAA?
Medicare sets each year’s IRMAA from your MAGI two years earlier, using the tax return the IRS has on file. Your 2026 premium comes from your 2024 return, your 2027 premium from 2025, and so on. It is a rolling chain, so income in any given year affects the premium two years out, not just once.
At what age should you stop doing Roth conversions?
There is no universal stop age; it depends on your goals and your Medicare timing. Because of the two-year lookback, the year you turn 62 is the last one whose income cannot raise a Part B premium, and 63 is the first that can. Many investors front-load conversions before 63 and then convert only up to an IRMAA threshold afterward, rather than stopping entirely.
At what income does IRMAA start in 2026?
For 2026, IRMAA begins above $109,000 of MAGI for single filers and above $218,000 for married couples filing jointly, based on 2024 income. Below those figures you pay the standard Part B premium of $202.90 per month. One dollar over the threshold triggers the full first-tier surcharge for each enrolled spouse.
Should I do Roth conversions before or after age 65 to avoid IRMAA?
To avoid IRMAA on a conversion, the relevant cutoff is 63, not 65, because of the two-year lookback into your age-65 Part B start. Converting before the year you turn 63 keeps the income off every Medicare premium. Converting after 63, including at 65, can raise premiums two years later, though it may still be worthwhile against future RMDs.
Can you appeal an IRMAA determination?
Yes, but only for qualifying reasons. If your income fell due to a life-changing event such as retirement, the death of a spouse, marriage, or divorce, you can file Form SSA-44 to ask Social Security to use more recent income. A voluntary Roth conversion is not a life-changing event, so it cannot be appealed away; the surcharge it causes stands.
Is there an IRMAA income cliff to avoid?
Yes. IRMAA is a cliff, not a phase-in. Crossing a threshold by a single dollar applies the entire tier’s surcharge to both spouses’ Part B and Part D. For a couple, the first tier at $218,001 MAGI adds roughly $2,297 for the year. Leaving a buffer below the nearest threshold is often more valuable than converting a few extra dollars.
