Roth conversions vs. ACA subsidies: the cliff every early retiree hits before 65
Retire before 65 and you land in a planning sweet spot: a stretch of low-income years, before Social Security and required distributions, that’s ideal for Roth conversions. But if you buy health insurance on the ACA Marketplace to bridge to Medicare, those conversions collide head-on with your premium subsidy — and in 2026 that collision is a cliff, not a slope. The enhanced subsidies expired at the end of 2025, so crossing 400% of the poverty line now forfeits your credit entirely. Here’s how the two interact, how to find the conversion “band” that fits, and a calculator that shows exactly where your cliff sits.
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1. The early-retiree gap years
There’s a golden window in many retirement plans: the years after you stop working but before Social Security, a pension in full force, and required minimum distributions push your income back up. In those low-income years, converting traditional retirement money to Roth at a low tax rate is one of the most valuable moves available — it’s the heart of the Roth conversion window.
But retire before 65 and you have a second problem to solve: health insurance until Medicare. For many early retirees without retiree coverage, that means the ACA Marketplace — where the price you pay is set by your income. And that’s where the conflict begins: the same low income that makes conversions attractive is also what earns you a big health-insurance subsidy, and conversions raise it.
2. Why conversions and subsidies collide
ACA premium tax credits are calculated from your modified adjusted gross income (MAGI) — essentially your AGI plus a few add-backs like tax-exempt interest and untaxed Social Security. A Roth conversion is fully taxable income, so it flows straight into AGI and therefore into MAGI.
So the two goals pull in opposite directions. Convert more, and you fill up low tax brackets and shrink future RMDs — but you also raise the income the Marketplace uses to size your subsidy. Every conversion dollar has a hidden second price tag: the subsidy it costs you. Below the cliff, that price is gradual. In 2026, at the cliff, it becomes a wall.
3. The cliff is back for 2026
From 2021 through 2025, temporary enhanced premium tax credits removed the old subsidy cliff: households above 400% FPL could still get help, capped at paying 8.5% of income for a benchmark plan. That made conversions far more forgiving — going over 400% cost subsidy gradually, not all at once.
The enhanced credits expired at the end of 2025 and were not extended. For 2026, the rules reverted to the original ACA framework: a hard cliff at 400% of the federal poverty level, with no premium tax credit at all above that line, plus higher required contribution percentages below it. A future extension has been debated but, as of mid-2026, is not law. Plan for the cliff.
That single change transforms Roth-conversion planning for ACA-covered early retirees. The binding limit is no longer just your tax bracket — it’s the 400% FPL line, where one extra dollar can cost your entire credit.
4. The two-sided squeeze
There’s a floor as well as a ceiling, and conversions can be used to manage both:
- The ceiling — 400% FPL. Above it in 2026, you get no premium tax credit. For a single filer that’s roughly $62,600 of MAGI; for larger households it’s higher.
- The floor — the Medicaid line. In states that expanded Medicaid, MAGI below about 138% FPL generally routes you to Medicaid instead of a subsidized Marketplace plan. Some early retirees deliberately convert enough to stay above that line and keep Marketplace coverage with subsidies.
- A middle bonus — cost-sharing reductions. Between 100% and 250% FPL, a Silver plan unlocks cost-sharing reductions that cut deductibles and out-of-pocket costs. Convert past 250% and those disappear too.
So an ACA-covered early retiree isn’t just avoiding a ceiling — they’re steering income into a target band that keeps subsidies (and maybe cost-sharing help) while converting as much as that band allows.
5. See your conversion vs. the cliff
Enter your household size, your income before any conversion, and the conversion you’re considering. The calculator finds your 400% FPL cliff, shows your headroom, and tells you whether the conversion keeps you under it or pushes you over.
Your numbers
400% FPL uses 2025 HHS poverty guidelines (48 contiguous states) applied to 2026 coverage. Crossing it in 2026 forfeits the entire premium tax credit. Ignores the Medicaid floor and state variations. Estimate only, not advice.
6. Finding your conversion band
The practical output of all this is a target income band for the year:
Say a couple has $60,000 of other MAGI and a 400% FPL cliff around $85,000. That leaves roughly $25,000 of conversion headroom before they lose their subsidy. Converting $25,000 captures low-bracket Roth space and keeps the credit; converting $40,000 pushes them over the cliff and forfeits it. The calculator above is really a headroom finder — the number it shows is how much you can convert before the subsidy disappears.
This band shifts every year with your other income, your household size, and the poverty guidelines — so it’s a yearly decision, not a set-and-forget one. Coordinate it with the rest of your retirement income tax picture.
7. When crossing the cliff still makes sense
Staying under 400% FPL is the default, but it isn’t a law of nature. There are years when deliberately blowing past the cliff is the right call:
- A large, one-time conversion to clear out a big traditional balance before RMDs or Social Security stack on top — taking the subsidy hit for one year to avoid higher taxes for twenty.
- A year you don’t need Marketplace coverage — for example, if a spouse’s employer plan or FEHB covers you, the ACA subsidy isn’t in play, so convert freely.
- The year you turn 65 and move to Medicare mid-year, ending the ACA calculation.
The point isn’t to worship the cliff — it’s to cross it on purpose, with the subsidy cost counted, rather than stumble over it by accident.
8. Watch the repayment risk
One last hazard specific to doing conversions on an ACA plan: premium tax credits are usually paid in advance, based on the income you estimated at enrollment. If a conversion pushes your actual MAGI over what you projected — and especially over 400% FPL, where the credit vanishes for 2026 — you can owe some or all of the advance credit back when you file.
Because the year’s income is clearer in November and December, many early retirees do their conversions at year-end. You can see how much room is left under the cliff, convert precisely up to it, and avoid an ugly reconciliation on the tax return. Just don’t forget conversions also feed into IRMAA two years later — another reason to size them deliberately.
9. Frequently asked questions
Do Roth conversions count as income for ACA subsidies?
Yes. A Roth conversion is taxable income that increases your adjusted gross income, and ACA premium tax credits are based on modified adjusted gross income (MAGI), which starts from AGI. So every dollar you convert raises the income the Marketplace uses to size your subsidy. For an early retiree buying coverage on the Marketplace before Medicare, a large conversion can shrink or eliminate the premium tax credit for that year.
Is the ACA subsidy cliff back in 2026?
Yes. The enhanced premium tax credits enacted in 2021 and extended through 2025 expired at the end of 2025 and were not extended. For 2026 the rules reverted to the original ACA structure: a hard subsidy cliff at 400% of the federal poverty level, with no premium tax credit at all above that line, and higher required contribution percentages below it. That makes crossing 400% FPL an abrupt all-or-nothing event rather than the gradual phase-out that applied from 2021 through 2025.
How much can crossing the cliff cost?
It depends on age, location, and premium, but the loss can be severe — especially for older pre-65 enrollees, whose unsubsidized premiums are highest. A single extra dollar of conversion income that pushes MAGI over 400% FPL can forfeit the entire premium tax credit, which for an older couple can run well over $10,000 to $20,000 a year. That is why the cliff, not the tax bracket, is often the binding constraint on how much an ACA-covered early retiree should convert.
What is the ideal conversion amount if I'm on an ACA plan?
There's no universal number, but the framework is to convert within a band. The floor is staying above the Medicaid threshold (about 138% FPL in expansion states) if you want Marketplace coverage with subsidies rather than Medicaid. The ceiling, in 2026, is keeping MAGI under 400% FPL to preserve any premium tax credit. Within that band you convert as much as your tax bracket and subsidy math justify. Some years it's worth deliberately blowing past the ceiling to convert a lot; most years it isn't.
Could a conversion trigger a repayment at tax time?
Yes. Premium tax credits are usually paid in advance based on your estimated income. If a Roth conversion pushes your actual MAGI higher than you estimated — and especially over 400% FPL, where the credit disappears entirely for 2026 — you may have to repay some or all of the advance credit when you file. Because of this, many early retirees do conversions late in the year, once income is more predictable, to avoid an unwelcome surprise on the tax return.