Find the optimal annual Roth conversion that fills your tax bracket without crossing the Medicare IRMAA cliff, between retirement and your RMD start age.
Auto-updated · Verified daily against IRS, Fed & Treasury sources
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Determines RMD start age (73 or 75).
Social Security + pensions + part-time work.
Based on your inputs
Fills your 12% bracket.
| Conversion window | 10 years (age 65–74) |
|---|---|
| Standard deduction (2026 est.) | $15,000 |
| Optimal annual conversion | $23,475 |
| Total convertible over window | $234,750 |
| Estimated federal tax on conversions | $28,170 |
| Remaining Traditional IRA after window | $215,250 |
| Year | Age | Convert | Cumulative | Remaining Trad IRA |
|---|---|---|---|---|
| 2028 | 65 | $23,475 | $23,475 | $426,525 |
| 2029 | 66 | $23,475 | $46,950 | $403,050 |
| 2030 | 67 | $23,475 | $70,425 | $379,575 |
| 2031 | 68 | $23,475 | $93,900 | $356,100 |
| 2032 | 69 | $23,475 | $117,375 | $332,625 |
| 2033 | 70 | $23,475 | $140,850 | $309,150 |
| 2034 | 71 | $23,475 | $164,325 | $285,675 |
| 2035 | 72 | $23,475 | $187,800 | $262,200 |
| 2036 | 73 | $23,475 | $211,275 | $238,725 |
| 2037 | 74 | $23,475 | $234,750 | $215,250 |
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The years between when you retire (and your earned income drops) and when Required Minimum Distributions begin (age 73 or 75 under SECURE 2.0). During this window, your taxable income is often at its lowest, making Roth conversions cheaper. Filling each year's tax bracket up to its top can save tens of thousands in lifetime taxes.
Medicare Income-Related Monthly Adjustment Amount (IRMAA) is a surcharge on Medicare Part B and Part D premiums for higher earners. The 2026 first-tier threshold is $106,000 single / $212,000 MFJ. Crossing by even $1 triggers a full surcharge tier — roughly $888/yr extra per person. IRMAA uses a 2-year MAGI lookback, so 2026 conversions affect 2028 premiums.
Backdoor Roth is for high earners during their working years — a $7K/yr workaround for the Roth IRA income limit. Roth conversion window is for pre-RMD retirees moving large Traditional IRA balances to Roth strategically over multiple years. Different problem, different audience.
Each conversion has its own 5-year clock for penalty-free withdrawal of the converted principal (under age 59½). Once you're 59½, the 5-year rule for converted dollars no longer applies for penalty purposes, but it still matters for tax-free earnings withdrawal.
No — this calculator uses federal brackets only. Add your state marginal rate to get true total tax cost. States like FL, TX, WA, NV, SD, WY, TN, NH, AK have no state income tax, making conversions cheaper there.
Conversion window: the years between retirement (income drops) and RMD start age (income rises again from forced withdrawals).
Optimal conversion = min(bracket headroom, IRMAA headroom). Fills your current marginal bracket without crossing into the next, while staying below the Medicare IRMAA surcharge cliff.
2026 IRMAA Tier 1: $106,000 single / $212,000 MFJ. Crossing by $1 triggers ~$888/yr Part B surcharge per person.
Every formula on this page traces to a federal agency, central bank, or peer-reviewed institution. We cite the rule-makers, not secondhand blogs.
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Calculations are for educational purposes only. Consult a qualified financial advisor for personalized advice.