ACA Subsidy Retirement Calculator

Health insurance is the quiet make-or-break of early retirement. Model your ACA premium subsidy year by year — and see how the income you report decides whether it's a few thousand dollars or twenty.

Retire before 65 and you leave employer health coverage behind with years to go until Medicare. The Affordable Care Act marketplace is how most early retirees bridge that gap, and its premium tax credits can be enormous — but they're calculated off one number you have surprising control over: your modified adjusted gross income (MAGI). For a retiree living off a portfolio, that isn't your spending. It's the taxable income you generate to fund it — and that makes ACA subsidies a planning variable, not a fixed cost.

The bridge years are a MAGI game

Because subsidies phase down as income rises, two early retirees who spend the same can pay wildly different premiums depending on where their spending money comes from. Drawing from a taxable brokerage realizes only the gains, not the whole withdrawal; Roth and cash withdrawals add little or nothing to MAGI; a large Roth conversion or an IRA withdrawal adds all of it. Sequencing those sources deliberately in the pre-65 window can hold your reported income in the range that keeps subsidies high — the same low-income window that's also prime territory for Roth conversions, which pulls the two goals into tension the calculator has to weigh together.

The cliff — and why one dollar can cost thousands

The sharpest edge is the subsidy cliff. Cross certain income thresholds — often by a single dollar of extra realized income — and a chunk of your premium tax credit can vanish at once. It's the one place in the tax code where a $1,000 raise really can cost you $20,000. Planning around it means knowing exactly where the edges sit for your household each year, which is precisely the kind of thing a spreadsheet gets wrong and an engine that models the actual rules gets right.

See the subsidy in your projection

The sample below is Robin, a single early retiree at 45 living off her portfolio. Living on portfolio withdrawals alone, her modeled income stays low enough to collect about $8,576 in ACA premium subsidies across her early bridge years (ages 45–53, today's dollars) — money the toy calculators leave out entirely. But it's a lever, not a given: run the aggressive Roth conversion schedule the optimizer suggests and most of that subsidy disappears, because the conversions push her MAGI up. That trade — subsidies now versus lower lifetime taxes later — is exactly what the calculator lets you weigh.

Want the deeper background first? Read about the ACA bridge from early retirement to Medicare and the cliff that can cost $20,000. Or jump straight to the full retirement calculator.