Roth Conversion Timing: When Is the Right Year to Do It?
Converting traditional IRA money to Roth creates immediate taxable income but eliminates future RMDs and creates tax-free growth forever. The math depends entirely on tax brackets — convert in low-bracket years, skip high-bracket years. Most retirees have a 5–13 year window between retirement and RMD start (age 73) where conversion math is most favorable.
Use the calculator
Roth Conversion Calculator
Step-by-step
- 1
Identify your low-bracket years
For most people: between job-end and Social Security claim age (typically 62–67), and between retirement and RMD start (73). Income drops from working salary to maybe portfolio withdrawals only — often pushing taxable income from 22–32% bracket down to 10–12% bracket.
- 2
Calculate the bracket fill
In 2026 single filer: $48,475 puts you at the top of the 12% bracket. Your retirement spending might be $40,000/year from taxable accounts (withdrawals not yet taxable) plus $0 from traditional IRA. You have $48,475 of "12% bracket headroom" — convert that much from traditional to Roth and pay only 12% on the conversion.
- 3
Avoid the IRMAA cliff
IRMAA (income-related Medicare premium surcharge) kicks in at $103,000 single / $206,000 joint MAGI in 2026. A Roth conversion that pushes you over either threshold raises Medicare Part B + D premiums by $80–$280/month for 12 months. Stay $10,000 below the threshold to leave buffer for capital gains and dividends.
- 4
Watch the Social Security taxation cliff
Up to 85% of Social Security becomes taxable based on combined income. Converting a chunk of traditional IRA can push more of your SS into the taxable zone. Use a tax calculator (your software or this site's Roth conversion calculator) to compute the marginal tax cost including the SS effect.
- 5
Convert annually, in November or December
Late-year conversion lets you see actual income from the year (capital gains, dividends, side income, etc.) before deciding the conversion amount. Aim to fill exactly to your target bracket without overshooting. Conversion deadline is December 31 of the conversion year.
- 6
Pay the tax from non-IRA money
Pay the conversion tax from taxable account money, not from the IRA itself. If you withdraw extra from the IRA to pay the tax, you reduce the converted amount AND owe early withdrawal penalty if under 59.5. Keep cash on hand for the tax bill.
- 7
Sequence with other tax events
In years with major tax events (large capital gain, business sale, severance payment), skip the conversion or do a smaller one. In years with tax losses (down market, business loss, large medical deduction), convert more aggressively. The strategy adapts annually.
💡 Tips
- Roth conversions cannot be undone after 2017 (the recharacterization option was eliminated by the Tax Cuts and Jobs Act). Do not convert more than you are certain about — it is a one-way door.
- For high-income years (last working year, large bonus year), do NO conversion. Save the strategy for genuinely low-income years.
- Roth conversions count as taxable income for the year — affecting student loan repayment plans (income-driven), ACA marketplace subsidies, and any other income-tested benefit. Plan accordingly.
FAQ
What is the 5-year rule for Roth conversions?
Each conversion has its own 5-year clock. Withdrawals of converted principal before the 5-year mark trigger a 10% penalty (if you are under 59.5). After 59.5, the 5-year rule still affects whether earnings withdrawn are tax-free. Most retirees doing conversions are over 59.5 anyway, simplifying the rules.
Can I convert from a 401(k) to a Roth IRA?
Yes, in two ways: (1) Roth conversion in-plan if your 401(k) supports it (about 70% do as of 2026), (2) Roll the 401(k) to a traditional IRA, then convert from the IRA to Roth IRA. The second method is more flexible and often used after retirement when you can choose any custodian.
Should I convert all my traditional IRA at once?
Almost never. A large lump-sum conversion typically pushes you into the 24%, 32%, or even 35% federal bracket plus state income tax. Spreading conversions over 5–15 years stays within lower brackets and saves substantial total tax. The only exception: if your future tax bracket is certain to be much higher (e.g., very high projected RMDs).
Does Roth conversion count toward Required Minimum Distribution?
No, RMDs and Roth conversions are separate. You must take the RMD first (cannot satisfy RMD with a conversion), then can do additional conversions on top. Once you start RMDs at 73, conversions become less beneficial because the RMD already creates taxable income that fills lower brackets.
Will Roth conversions raise my Medicare premiums?
Possibly. IRMAA (Income-Related Monthly Adjustment Amount) looks at MAGI from 2 years prior. Conversions in 2026 affect 2028 Medicare premiums. Stay below $103K single / $206K joint MAGI to avoid the surcharge, or accept the surcharge as the cost of the conversion if the long-term benefit outweighs it.