Picture two early retirees with identical $500,000 traditional IRAs. One converts the whole balance in a single year. The other converts $50,000 a year for ten years. The first pays roughly $130,000 in tax. The second pays roughly $60,000. Same money, same destination, $70,000 difference, and the entire gap comes from how much you convert each year in a Roth conversion ladder. That is the most expensive sizing mistake in early retirement, and it is completely avoidable.
The rule of thumb is simple: convert about one year of living expenses per year, sized to fill your target tax bracket without spilling into the next one. Here is how to apply it to your own numbers.
The bracket-filling formula
Each year, your conversion room equals the top of your target bracket minus your other taxable income. That is the whole calculation:
Say you are married, retired at 55, with $5,000 a year of part-time income and you are targeting the top of the 12% bracket. In 2026 the 12% bracket tops out around $100,800 of taxable income for married couples filing jointly. Subtract the $5,000 and you can convert about $95,800 at 12% or below. That is your room. Convert more and the excess spills into the 22% bracket, where every extra dollar costs you nearly twice as much in tax.
For singles, the 2026 12% ceiling sits around $50,400. The 22% bracket, which is the common target for people with larger IRA balances racing RMDs at 73, tops out near $105,700 single and $211,400 married. Most early retirees I have seen model this land in one of two camps: fill the 12% bracket if you expect to stay in a low bracket forever, or fill the 22% or 24% bracket if you have a large balance and future required minimum distributions would push you into higher rates anyway.
A worked example: age 52, $700k IRA, $55k spending
| Year | Age | Convert | Tax at ~10-12% | Unlocks |
|---|---|---|---|---|
| 1 | 52 | $45,000 | ~$2,000 | Age 57 |
| 2 | 53 | $45,000 | ~$2,000 | Age 58 |
| 3 | 54 | $45,000 | ~$2,000 | Age 59 |
| 4 | 55 | $45,000 | ~$2,000 | Age 60 |
| 5 | 56 | $45,000 | ~$2,000 | Age 61 |
Five years of $45,000 conversions at a low effective rate, about $2,000 of tax per year, and the first rung unlocks right when this retiree needs it at 57. Total converted over the full ladder: $450,000 for roughly $20,000 of tax, an effective rate around 4%. Compare that to converting while still working in the 24% bracket, and the savings are close to $90,000. The strategy is just patience plus arithmetic.
Do not forget the 5-year clock
Each conversion starts its own five-year clock. Money converted in 2026 becomes available for penalty-free withdrawal of principal on January 1, 2031. That means you need five years of bridge funding, living expenses covered from taxable brokerage accounts, savings, or Roth IRA contributions, which can always be withdrawn, before the first rung matures.
This is where sizing goes wrong in the other direction. People convert too little because they are scared of the tax bill, then discover at 54 that they cannot touch the money they need at 55. Size the conversion to one year of spending, not to what feels comfortable on the tax return. The tax is the price of admission; the ladder only works if the rungs are big enough to stand on.
Recalibrate every year
Your income will not match your projection. Part-time work pays more or less than expected, dividends land differently, a side project takes off. So the conversion amount is not a set-and-forget number. Each fall, project your actual taxable income for the year, subtract it from your target bracket ceiling, and convert exactly the room that remains. The people who get the most out of this strategy treat December like a tuning session, not a deadline.
One more consideration: if you are still years from retirement, model the ladder now rather than improvising later. The five-year clock means your first conversion should happen five years before you need the money:
Model your Roth conversion ladder free
The calculator lets you plug in your balance, annual conversion, and other income, then shows the tax per year, the total converted, and when each rung unlocks. Start with one year of spending as the conversion amount and adjust from there.
Frequently asked questions
How much should you convert each year?
About one year of living expenses, sized to fill your target tax bracket without spilling into the next. Many early retirees target the top of the 12% bracket: roughly $50,400 single or $100,800 married filing jointly in 2026.
How does the 5-year rule work?
Each conversion starts its own 5-year clock. Converted principal can be withdrawn tax and penalty-free after five years, so you need five years of bridge funding from taxable accounts.
All at once or spread over years?
Spread. Converting $500,000 at once can push much of it into the 32% or 35% bracket; $50,000 a year for ten years keeps each conversion in lower brackets and can save roughly $70,000 in tax.
Should I convert into the 22% or 24% bracket?
If you expect an equal or higher bracket later, especially once RMDs start at 73, filling 22% or 24% can make sense. If you expect low income indefinitely, stick with the 12% bracket.
Do you pay taxes on a Roth conversion?
Yes, ordinary income tax on the converted amount in the year of conversion. The strategy shines in low-income years like early retirement.
Sources: ChooseFI, "Roth Conversion Ladder: Access Retirement Funds Early Without Penalties"; Levy Financial, "Roth IRA Conversion Tax Strategy 2026"; SDO CPA, "Roth Conversion Strategies for 2026." Bracket figures are 2026 federal thresholds; verify against IRS publications. Figures verified October 2026.