A conversion ladder converts a slice of a traditional IRA every year during the low-income gap between retirement and required minimum distributions, paying today's low-bracket tax to shrink the forced withdrawals of tomorrow. This calculator runs the ladder year by year against the 2026 brackets and the IRS RMD table, then totals a lifetime of taxes both ways so you can see what the window is actually worth.
Between the last paycheck and Social Security, most retirees report very little taxable income. Every bracket below their retirement-year bracket sits empty, and the standard deduction sits empty with them. A Roth conversion in an ordinary working year stacks on top of a full salary and gets priced at the top marginal rate. The same conversion in a gap year lands in brackets that may never be open again. A ladder is simply the discipline of converting one year at a time, never exceeding a chosen bracket top, until the traditional balance is small enough that future required minimum distributions stop doing damage.
The clock matters as much as the rate. Social Security benefits become up to 85 percent taxable once other income rises (IRS Pub 915), and at 73 or 75, depending on birth year under SECURE 2.0, the IRS forces withdrawals from every traditional dollar left, using the Uniform Lifetime Table divisors from Publication 590-B. An untouched seven-figure IRA can push RMD income into the 22 or 24 percent bracket for life. The ladder trades a known, chosen tax now for that forced, larger tax later.
Variables in plain terms. The target bracket top is the taxable income ceiling you set for each conversion year; the 2026 tops are $50,400 and $100,800 for the 12 percent bracket, single and joint, and $105,700 / $211,400 for the 22 percent bracket. Other income includes everything taxable besides the IRA, plus 85 percent of Social Security once claimed. The deduction is the 2026 standard deduction, $32,200 joint or $16,100 single. The RMD side uses the Uniform Lifetime Table, so a 73-year-old divides the prior year-end balance by 26.5. Both scenarios pay tax on the same other income; the difference is conversion taxes added in the gap years versus RMD taxes removed afterward, through age 90.
A married couple retires at 60 with $1,000,000 in a traditional IRA, no other income, and a $45,000 Social Security benefit they claim at 67. They cap each year at the top of the 12 percent bracket. With $32,200 of standard deduction to consume, that allows a $133,000 conversion each year taxed at $11,600, a blended 8.72 percent. From 67 the taxable part of Social Security, $38,250, eats into the room, so the annual conversion drops to $94,750 at $10,995 of tax. The balance grows while it drains, so the total converted by age 69 comes to $1,214,301.63, more than the starting balance, for a total conversion tax of $114,071.20, a blended 9.39 percent.
| Age | Conversion | Conversion tax | IRA left (year-end) |
|---|---|---|---|
| 60–66 (each year) | $133,000.00 | $11,600.00 | $910,350.00 → $270,068.94 |
| 67–68 (each year) | $94,750.00 | $10,995.00 | $184,084.89 → $93,801.63 |
| 69 (final) | $93,801.63 | $10,881.20 | $0.00 |
| Total | $1,214,301.63 | $114,071.20 (9.39%) | — |
Now compare against leaving the account alone. Untouched, the IRA compounds to $1,885,649.14 by the end of age 72, and the first RMD at 73 is $71,156.57, taxed as ordinary income on top of Social Security. Through age 90, the no-ladder path pays $257,709.46 of federal tax; the ladder path pays $128,591.20 including every conversion bill. The gap is worth $129,118.26, and the ladder couple also ends with a Roth that keeps growing tax-free with no RMDs attached to it.
Run the defaults with a 0 percent return and the verdict flips: the ladder loses $18,774.53. A stagnant million dollars forces only modest RMDs taxed in the low brackets, so the $89,105 paid to convert everything buys almost nothing. A late start cheapens the strategy too: begin at 69 and only four gap years remain, cutting the lifetime savings to $7,050.78. The honest reading is that the ladder is a bet on three conditions at once, a large balance, a long low-income window, and real compounding, and it fails when any one of them is missing. The calculator exists precisely so the bet can be priced before it is placed.
Size matters at the top end as well. A $2,000,000 balance filling the 22 percent bracket converts about $2,488,478 over the window for $384,445 of tax and saves $268,102.70 by 90, but each conversion year lands $243,600 of MAGI on the tax return, which is why the two-year IRMAA lookback deserves a check before every December deadline. The single-conversion version of that trade-off is covered in the Roth Conversion Calculator, and the premium cliffs themselves in the Medicare IRMAA Calculator.
Once the ladder is done, the money sits in a Roth with no required withdrawals, which changes how the whole portfolio funds retirement. The Retirement Withdrawal Calculator models the spending order across taxable, traditional, and Roth accounts after the conversions are complete.
In those years most retirees have little or no taxable income, so the standard deduction and the lowest brackets sit empty. A conversion stacks on top of that low base and can be taxed at rates in the single digits or low teens. Once Social Security starts, up to 85 percent of the benefit becomes taxable income, and once required minimum distributions start at 73 or 75, the IRS forces taxable withdrawals whether the money is needed or not. The ladder's entire edge comes from moving money across those low-rate years before the forced-income years arrive.
Pick the highest bracket you are willing to pay and convert up to its top, no further. The room in a year equals the top of the target bracket minus your other taxable income for that year, and when your other income is below the standard deduction the room grows by that deduction. At the calculator defaults that is 100,800 plus 32,200, or 133,000 dollars of conversion per year taxed at an 8.72 percent blended rate. Converting past the bracket top raises the average price of every dollar moved that year, which is why the calculator caps each year at the boundary.
Yes, for the accounts you empty. Roth IRAs have no RMDs during the original owner's lifetime, and Roth 401(k) accounts have been exempt since 2024 under SECURE 2.0. At the calculator defaults the ladder converts the balance to zero by age 69, so the first RMD at 73 is nothing instead of the 71,157 dollars the untouched IRA would have forced. Any balance left in the traditional account still produces RMDs, which is why the plan targets converting the entire balance if the window is long enough.
When the money would not have grown much, the avoided RMD taxes are small and the conversion taxes are paid for nothing. Set the return to zero percent at the defaults and the ladder loses 18,775 dollars over the horizon, because a stagnant 1,000,000 dollar IRA only ever forces modest RMDs taxed in the low brackets. A short window hurts the same way: starting at 69 leaves only four conversion years and cuts the lifetime savings to about 7,051 dollars. The strategy rewards large balances, long windows, and real growth, and it deserves skepticism in flat markets or late starts.
Each conversion adds its full amount to MAGI, and Medicare premiums are set from the tax return filed two years earlier, so conversions in your 60s set the premiums you pay from 65 on. At the defaults a married couple converting 133,000 dollars a year with no other income sits far below the first 2026 IRMAA threshold of 218,000 dollars for joint filers, per CMS. Someone with 150,000 dollars of other income would cross it. Check the Medicare IRMAA calculator before fixing each year's conversion amount, especially in the two years before Medicare enrollment.
From savings outside the retirement accounts. The calculator assumes exactly that, so the traditional balance drops only by the converted amount. Paying the tax from the account itself shrinks the amount that compounds tax-free and, before age 59 and a half, any tax withheld from the conversion counts as a distribution carrying the 10 percent early-withdrawal penalty. A ladder planned in a 60-year-old's first retirement years has a second reason to keep outside cash: the tax bills start arriving immediately, seven or more years before any Roth withdrawal is needed.