If you are like most American retirees, the bulk of your savings sits in a traditional IRA or a 401(k) that you contributed to over decades. Those accounts are tax-deferred — you got a tax deduction when you put the money in, but every dollar you take out in retirement is taxed as ordinary income. For many retirees, this works out fine. For others, it produces a problem most people do not see coming until they hit it: a tax bomb in their seventies and eighties.
The tax bomb has two main triggers. The first is Required Minimum Distributions (RMDs), which currently start at age 73 (increasing to 75 starting in 2033 under the SECURE 2.0 Act) and force you to withdraw a percentage of your traditional retirement accounts every year, whether you need the money or not. As your account balance grows and the required withdrawal percentage increases, those forced withdrawals can push you into much higher tax brackets, increase the share of your Social Security that gets taxed, and even bump up your Medicare premiums through a surcharge called IRMAA. The second trigger is what happens to your heirs: under the SECURE Act, most non-spouse heirs must drain inherited traditional IRAs within 10 years, which can push them into the highest tax brackets during their peak earning years.
A Roth conversion ladder is the most effective strategy retirees have for defusing this tax bomb. It works by moving money out of the traditional account and into a Roth IRA gradually, year by year, paying the taxes upfront. Once money is in the Roth, it grows tax-free for the rest of your life, never has RMDs, and passes to heirs who can also withdraw it tax-free. The cost is paying the taxes now instead of later. For many retirees, the math works out enormously in their favor — but only if you do the conversions in the right years, in the right amounts.
The years between when you stop working and when RMDs start are the most valuable years of your tax life, and almost no one fully exploits them. Here is why.
Once you stop earning a paycheck, your taxable income drops sharply. If you have not yet started Social Security or you have started it modestly, your income may be very low for several years — sometimes low enough that you are in the 10 or 12 percent federal tax bracket. This is a window in which you can move money out of your traditional IRA and into a Roth IRA at very low tax cost, often paying a small fraction of the rate you would pay if you waited.
Once RMDs kick in at age 73, your taxable income jumps dramatically. The required withdrawals are taxable. They push you into higher brackets. They affect Social Security taxation and Medicare premiums. The window for cheap conversions is essentially closed.
The right way to think about it is this: every dollar you convert during the low-income years of your sixties costs you a known small amount in taxes today. Every dollar that stays in the traditional account beyond age 73 is going to cost you and your heirs a much larger, harder-to-control amount in taxes over the years that follow. Pre-paying at the lower rate is almost always the better deal.
The optimal target is usually to convert just enough each year to fill up your current tax bracket without spilling into the next one. If you are in the 12 percent bracket and the top of that bracket is at $100,000 of taxable income, and your other income is $40,000, you can convert about $60,000 from your traditional IRA to your Roth this year and pay only the 12 percent rate on the conversion. The next year, you do it again. Over the course of five to ten years, you can move six figures of money into your Roth at a very low effective tax rate.
A Roth conversion is technically simple. You contact the broker holding your traditional IRA (Vanguard, Fidelity, Schwab, etc.) and tell them you want to convert a specified dollar amount from your traditional IRA to a Roth IRA. The broker moves the money. The amount converted gets added to your taxable income for the year. You owe income tax on the converted amount when you file your taxes the following spring. From that moment forward, the converted money lives in your Roth IRA and grows tax-free.
There are no income limits on Roth conversions (unlike Roth contributions, which have income limits). Anyone with a traditional IRA can convert any amount, in any year, regardless of how much they earn. There is no annual cap on how much you can convert. You can convert $10,000 or $200,000 in a single year — the only limit is what you are willing to owe in taxes.
Pay the conversion taxes from outside the IRA, not from the IRA itself. If you let the broker withhold the taxes from the converted amount, you lose the tax-free growth on the money used for taxes, and (if you are under 59½) you also pay a 10 percent early withdrawal penalty on it. Always pay the taxes from a regular checking or savings account, never from the converted balance.
Make estimated tax payments if your conversion is large enough. The IRS expects you to pay taxes throughout the year, not just on April 15. If you convert a large amount in March, you should make an estimated tax payment by the relevant quarterly deadline to avoid an underpayment penalty.
The amount to convert each year depends on your tax bracket, your other income, and your overall plan. Here is the basic framework.
Step one: Estimate your taxable income for the year before any conversion. Add up Social Security (if you are taking it) at 85 percent, any pension or annuity income, any interest or dividends, and any wages. Subtract the standard deduction. The resulting number is your starting taxable income.
Step two: Find the top of your current tax bracket. The 12 percent bracket for married couples filing jointly currently extends to approximately $96,950 of taxable income. The 22 percent bracket extends to approximately $206,700. Note: These brackets assume the 2017 Tax Cuts and Jobs Act was extended. If it was not extended, brackets would revert to higher pre-2017 rates — consult a tax advisor for the current rates. These are the brackets where most retirees should be doing their conversions, because the rates are reasonable.
Step three: Subtract your starting taxable income from the top of the bracket you want to fill. The difference is the amount you can convert this year while staying in that bracket. For example: starting income of $30,000, target bracket top of $96,950, conversion amount of roughly $67,000.
Step four: Consider whether to push into the next bracket. Sometimes it makes sense to spill over into the next bracket, especially if you have a lot of money to convert and limited years to do it. The 22 percent bracket is still a reasonable rate and may be lower than what you would pay later under RMDs. Doing the math on a year-by-year basis is what separates a good Roth conversion strategy from a great one.
Step five: Be aware of the secondary effects. Conversions count as income for purposes of Medicare premiums (IRMAA), Social Security taxation, and the Net Investment Income Tax. A conversion that pushes your income above certain thresholds can cause unexpected costs in those areas. A good tax planner can help you find the sweet spot.
<div style="max-width:640px;margin:2rem auto;background:#FFFFFF;border-radius:12px;box-shadow:0 2px 12px rgba(27,40,56,0.10);overflow:hidden;font-family:system-ui,-apple-system,sans-serif;" role="figure" aria-label="Chart showing 2026 federal tax brackets for married filing jointly"> <div style="background:#1B2838;padding:16px 24px;"> <h3 style="margin:0;font-family:Georgia,serif;color:#FFFFFF;font-size:1.15rem;font-weight:700;">2026 Tax Brackets: The Roth Conversion Sweet Spot</h3> <p style="margin:4px 0 0;color:#A0B0C0;font-size:0.82rem;">Married Filing Jointly — fill the lowest brackets first</p> </div> <div style="padding:24px;"> <!-- 10% bracket --> <div style="display:flex;align-items:stretch;margin-bottom:6px;border-radius:8px;overflow:hidden;"> <div style="width:60px;background:#2E7D32;display:flex;align-items:center;justify-content:center;padding:12px 0;"> <span style="color:#FFFFFF;font-weight:700;font-size:1rem;">10%</span> </div> <div style="flex:1;background:#E8F5E9;padding:12px 16px;display:flex;align-items:center;justify-content:space-between;"> <span style="font-size:0.88rem;color:#1B5E20;font-weight:500;">$0 — $23,850</span> <span style="font-size:0.78rem;color:#2E7D32;font-weight:600;background:#C8E6C9;padding:2px 8px;border-radius:4px;">Best rate</span> </div> </div> <!-- 12% bracket --> <div style="display:flex;align-items:stretch;margin-bottom:6px;border-radius:8px;overflow:hidden;"> <div style="width:60px;background:#1565C0;display:flex;align-items:center;justify-content:center;padding:12px 0;"> <span style="color:#FFFFFF;font-weight:700;font-size:1rem;">12%</span> </div> <div style="flex:1;background:#E3F2FD;padding:12px 16px;display:flex;align-items:center;justify-content:space-between;"> <span style="font-size:0.88rem;color:#0D47A1;font-weight:500;">$23,851 — $96,950</span> <span style="font-size:0.78rem;color:#1565C0;font-weight:600;background:#BBDEFB;padding:2px 8px;border-radius:4px;">Sweet spot</span> </div> </div> <!-- 22% bracket --> <div style="display:flex;align-items:stretch;margin-bottom:6px;border-radius:8px;overflow:hidden;"> <div style="width:60px;background:#E65100;display:flex;align-items:center;justify-content:center;padding:12px 0;"> <span style="color:#FFFFFF;font-weight:700;font-size:1rem;">22%</span> </div> <div style="flex:1;background:#FFF3E0;padding:12px 16px;display:flex;align-items:center;justify-content:space-between;"> <span style="font-size:0.88rem;color:#BF360C;font-weight:500;">$96,951 — $206,700</span> <span style="font-size:0.78rem;color:#E65100;font-weight:600;background:#FFE0B2;padding:2px 8px;border-radius:4px;">Use caution</span> </div> </div> <!-- 24%+ --> <div style="display:flex;align-items:stretch;border-radius:8px;overflow:hidden;"> <div style="width:60px;background:#78909C;display:flex;align-items:center;justify-content:center;padding:12px 0;"> <span style="color:#FFFFFF;font-weight:700;font-size:0.9rem;">24%+</span> </div> <div style="flex:1;background:#ECEFF1;padding:12px 16px;display:flex;align-items:center;"> <span style="font-size:0.88rem;color:#455A64;font-weight:500;">$206,701 and above — typically avoid converting at these rates</span> </div> </div> <!-- Strategy note --> <div style="margin-top:16px;padding:12px 14px;background:#F5F3EE;border-radius:8px;border-left:4px solid #1565C0;"> <p style="margin:0;font-size:0.85rem;color:#1B2838;line-height:1.5;"><strong>Strategy:</strong> Convert enough each year to "fill up" the 10% and 12% brackets without spilling into 22%. If your other income is $40K, you can convert ~$57K at only 12%.</p> </div> </div> <div style="padding:0 24px 16px;text-align:right;"> <span style="font-size:0.72rem;color:#90A4AE;">Source: IRS Revenue Procedure, 2026 MFJ brackets</span> </div> </div>
Mistake one: Waiting too long. The biggest single mistake is delaying conversions until your sixties are mostly over, leaving too little time to do meaningful conversions before RMDs hit. The earlier in retirement you start (within reason), the more years you have to spread conversions over and the lower the tax cost in any single year. If you are 62 and just retired, this is the perfect moment to start planning.
Mistake two: Converting too much in one year. Some retirees, eager to get the strategy done, convert huge amounts in a single year and end up in much higher tax brackets than necessary. The point of the ladder is to spread the conversions across years to keep each year's tax rate low. Patience produces better outcomes.
Mistake three: Forgetting about Medicare and Social Security effects. As mentioned, conversions affect more than just income tax. They can increase your Medicare premiums for two years after the conversion year (because Medicare looks at your tax return from two years ago to set premiums) and can increase the share of your Social Security that gets taxed. A surprise IRMAA increase can make a conversion look much worse than the simple tax math suggests.
Mistake four: Doing it without professional advice. Roth conversions are one of the few financial decisions where a few hundred dollars spent on a fee-only tax planner or CPA can save you tens of thousands of dollars over your lifetime. The math is complex enough that DIY can produce expensive mistakes. Find someone who specializes in retirement tax planning and have them run the numbers for your specific situation. The cost of the consultation will pay for itself many times over.
If leaving money to children or grandchildren is part of your plan, Roth conversions become even more powerful. Under current law, most non-spouse heirs must drain an inherited traditional IRA within 10 years of inheriting it. For a child in their fifties at the peak of their career, that forced withdrawal can mean adding $50,000 to $200,000 of taxable income each year for a decade — pushing them into the highest federal tax brackets and producing a large lifetime tax bill on what should have been a gift.
Inherited Roth IRAs work differently. The 10-year withdrawal rule still applies, but the withdrawals are tax-free. The heirs receive the full value of the account, with no tax bill at all. For a child in a high tax bracket, this can mean the difference between receiving $300,000 and receiving $200,000 from the same starting amount.
If you are doing Roth conversions partly to benefit your heirs, the strategy is one of the most generous gifts you can give them — and unlike many gifts, this one costs you almost nothing extra, because you would have owed similar taxes anyway. You are simply paying the bill at your lower tax rate now instead of letting them pay it at their higher tax rate later.
If this strategy sounds like it might fit your situation, here is the next step. Do not call your IRA broker and start converting today. Instead, do this: in the next few weeks, schedule a meeting with a fee-only retirement tax planner or CPA who specializes in this area. Bring your most recent tax return, an estimate of your other income for the year, a list of your retirement accounts and balances, and your Medicare information if you are 65 or over. Ask them to run a multi-year Roth conversion analysis for your situation.
The analysis should show you, year by year, how much to convert, what the tax cost would be, what the lifetime tax savings look like, and how the strategy interacts with Medicare premiums and Social Security taxation. A good analysis takes a few hours of work and typically costs $300 to $1,000. The savings, for the right retiree, are often dramatic — and they compound over the rest of your life.
Roth conversions are one of the few areas of retirement planning where small actions taken at the right time can make six-figure differences over a lifetime. The window is now, while you are between work and RMDs. The window does not stay open. Use it.
