A calculator can tell you the number. It can't tell you whether it's the right year to trigger it.
Frank Delgado is 61. The night before his call with Kevin Lum, he ran his numbers through an online Roth conversion calculator that promised roughly $600,000 in lifetime tax savings if he converted his entire IRA over five years. He walked into the meeting ready to sign the paperwork.
Kevin hears versions of this story often. Roth conversion calculators are everywhere, and they all produce the same clean, confident number. What most don't show is how fragile that number actually is.
In his video “Don't Do a Roth Conversion – Until You Watch This”, Kevin breaks down why conversion projections rest on what he calls a “tower of guesses” — future tax rates, inflation, investment returns, even the order in which spouses pass away — and why changing one input can flip the entire answer. Below is the framework he walks clients through before converting a single dollar.
Why the Calculator's Number Isn't the Whole Story
A Roth conversion projection has to assume decades of unknowns at once. Move any one of them and a six-figure savings estimate can shrink, disappear, or reverse. That doesn't make the calculator useless — Kevin still runs one with nearly every client — but the number on the screen is a directional signal, not a promise.
Seven Situations Where a Roth Conversion May Not Make Sense
1. The Account Will Be Spent Down Anyway
Someone in their early 60s with a modest tax-deferred balance who plans to spend most of it during retirement gets little benefit from converting. The same goal — controlling which tax bracket the money comes out in — can usually be reached by simply spending the account down and staying near the top of a target bracket.
Ask yourself: Am I planning to spend down this account myself, or is it money I expect to leave behind?
2. Charitable Giving Is Already Part of the Plan
For someone planning to give a significant portion of their assets to charity, qualified charitable distributions can satisfy required minimum distributions after age 70½, up to a set annual limit, without that money ever being taxed. That tool alone can offset much of the RMD pain a conversion is meant to solve — which makes converting less necessary, sometimes not worth doing at all.
Ask yourself: How much of what I'm considering converting would eventually go to charity anyway?
3. It Could Trigger an IRMAA Surcharge
Medicare premiums are means-tested, and IRMAA thresholds work like a cliff: one dollar over, and the full surcharge applies to the entire premium, not just the amount above the line. It also runs on a two-year lookback, so a conversion today doesn't show up as a larger Medicare bill until two years later — often catching people off guard.
Ask yourself: Do I know which IRMAA threshold I'm closest to this year?
4. It Could Cost an ACA Subsidy
For someone retiring before 65 and buying coverage on the marketplace, income is the main lever behind the subsidy. Cross 400% of the federal poverty line by even a dollar, and the entire subsidy can disappear, not just the portion above the line. A large conversion in the wrong year can turn an affordable health plan into a far more expensive one.
Ask yourself: How much would a conversion this size affect my health insurance costs?
5. It Could Erase the Senior Deduction
Retirees over 65 currently have access to an additional deduction that phases out past a certain income level. Converting aggressively in a single year can push income high enough to erase some or all of it — an offsetting cost a basic calculator rarely shows.
Ask yourself: Would this year's conversion push my income past the point where this deduction starts phasing out?
6. The Tax Bill Isn't Comfortably Affordable This Year
A conversion is only worth doing if the resulting tax bill can be paid without strain, ideally from cash outside the retirement account. Clients often agree to a projected bill in theory but feel differently once it arrives. If paying it means selling assets at an inconvenient time, that's a signal to convert less, not more.
Ask yourself: Could I write the check for this year's conversion taxes without touching money I need for something else?
7. It Could Increase Sequence-of-Return Risk
A conversion is a voluntary withdrawal in a year that wasn't required. If markets drop the same year a large conversion happens, assets may need to be sold at a loss to cover both the tax bill and ordinary spending, shrinking the portfolio at the worst possible moment for it to recover.
Ask yourself: What would this conversion plan look like if the market dropped 20% the year I did it?
Before Converting: A Quick Self-Check
A quick self-assessment. Answer honestly — this is a self-check, not a test.
Watch the Full Breakdown
Kevin walks through each of these situations in more detail, with real client examples, in his video “Don't Do a Roth Conversion – Until You Watch This”. The Retirement Made Simple podcast covers many of the same trade-offs in more depth: listen to the episode here.
Related from Retirement Made Simple:
Not Sure Whether a Conversion Makes Sense This Year?
IRMAA thresholds, ACA subsidies, tax brackets, and available cash all shift year to year — which is exactly why a conversion that made sense last year may not make sense this year.
Readers can also run their own numbers with the 5-Minute Retirement Plan Calculator.
Book a Free Roth Conversion Strategy Session
A 30-minute conversation to look at whether converting makes sense this year, and how much. No cost. No obligation. No sales pitch.
Frequently Asked Questions About Roth Conversions
When Should I Not Do a Roth Conversion?
A Roth conversion may not make sense when the account will simply be spent down during retirement, when charitable giving already covers RMDs through qualified charitable distributions, when the added income would trigger an IRMAA surcharge or cost an ACA subsidy, when it would erase the senior deduction, or when the tax bill can't comfortably be paid from cash outside the account. Converting in a market downturn can also raise sequence-of-return risk.
What is the IRMAA surcharge and how does it relate to Roth conversions?
IRMAA is a Medicare premium surcharge tied to income, and it works like a cliff: crossing a threshold by even one dollar applies the full surcharge to the entire premium, not just the amount above the line. It also runs on a two-year lookback, so a conversion done this year doesn't show up as a higher Medicare bill until two years later.
Can a Roth conversion affect ACA health insurance subsidies?
Yes. For someone retiring before 65 and buying coverage through the marketplace, income determines the subsidy. Crossing 400% of the federal poverty line by even a dollar can eliminate the entire subsidy, not just the portion above the line, turning an affordable health plan into a much more expensive one.
Is a Roth conversion calculator accurate?
Calculators are useful directionally but shouldn't be treated as a guarantee. Every projection assumes future tax rates, inflation, and investment returns, and changing any one assumption can significantly change the result. The better use is to see whether converting leans clearly in one direction, not to treat the exact figure as certain.
Who should consider a Roth conversion?
Roth conversions tend to make the most sense for people who won't spend down the entire account, who want to reduce a future surviving spouse's tax burden (the widow's penalty), or who want to leave heirs a more tax-efficient inheritance. The key is the right amount for the specific year, not converting a large lump sum all at once.
Kevin Lum, CFP® | Retirement Made Simple
This article is companion content to the Retirement Made Simple YouTube channel. It is for informational purposes only and does not constitute personalized financial advice.
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