Early-retirement tax strategy

Roth conversion ladder calculator

A Roth conversion ladder is how early retirees reach money that is locked in a traditional 401(k) or IRA. Each year you convert a slice to a Roth, pay ordinary income tax on it, and five years later that slice is withdrawable penalty-free at any age. Stack the conversions and the maturities become a ladder of accessible money. The same moves also drain the traditional balance that would otherwise force required distributions in your seventies — which is usually where most of the money is saved.

$108,575 less lifetime tax — 20 rungs from 50, in today's dollars

Converting $70,000/yr from age 50 moves $1,362,556 into the Roth over 20 years, at a cost of $128,435 in conversion tax. Total lifetime tax falls from $297,777 to $189,201, required distributions at 75 drop from $66,671 to $0, and the plan ends at 92 with $2,464,726 instead of $2,433,152.

6% return · 3% inflation

How the ladder is built

The mechanics are simple and the timing is everything:

The five-year clock is per conversion. Money converted this year becomes withdrawable penalty-free five tax years from January 1 of this year. So a ladder needs to start about five years before you want to spend from it. Here the first rung, converted at 50, opens at 55; the taxable account runs dry at 56: 10% penalties before 59½ are $0 with the ladder and $37,357 without it.
The conversion is taxable now, at your rates. There is no penalty on a conversion at any age, but the full amount is ordinary income in the year you convert. The whole strategy rests on converting in years when your rate is unusually low.
The gap years are the opportunity. Between retiring and the arrival of Social Security and required distributions, taxable income can be near zero. In the plan above, ages 50 to 69 are spent filling low brackets on purpose while the taxable account, then the maturing rungs, fund actual living costs.
Converted amounts come out before earnings. Roth withdrawal ordering puts contributions and conversions ahead of earnings, so an early retiree tapping a ladder is generally reaching already-taxed money.

The ladder, year by year

A couple retiring at 50 with $1,500,000 in a traditional 401(k), $500,000 in a taxable account, spending $50,000/yr, Social Security at 70. Converting $70,000/yr in today's dollars from 50, all figures deflated to today's dollars:

Roth conversion ladder from 50 → the traditional balance drains and the RMD disappears
Age	Converted	Traditional balance	Roth balance	RMD without the ladder
50	$70,000	$1,520,000	$70,000	—
55	$70,000	$1,383,644	$451,796	—
60	$70,000	$1,124,009	$587,780	—
75	—	$0	$1,595,149	$66,671
80	—	$0	$1,808,497	$75,870

The traditional account is empty by 70: $0 at 73 with the ladder versus $1,647,518 without it. That is why the required-distribution column on the right never appears in the ladder version — there is nothing left to require. Left alone, that same balance forces $66,671 of taxable income at 75 whether the household needs the cash or not, stacked on top of Social Security.

Is it worth it? Read the honest version

In this scenario, yes — and by two independent measures, which is the test that matters. Lifetime tax is $108,575 lower in today's dollars, and real net worth at 92 is $31,574 higher. Both point the same way, so the saving is not an artifact of when the tax was paid. But the result is scenario-specific, and it is easy to find plans where a ladder is roughly neutral or mildly negative:

Converting into a higher rate than you'll retire at simply prepays tax. The gap years work because income is low; a ladder run in a high-income year does the opposite.
Paying the conversion tax from the portfolio costs you decades of compounding on that money. The $128,435 of tax here leaves the plan early, when it is most expensive.
Before 65, conversions collide with ACA premium credits. A conversion is MAGI, and crossing 400% of the poverty level forfeits the entire premium subsidy. In the pre-Medicare years the credit is frequently worth more than the conversion saves.
From 63, conversions collide with Medicare IRMAA on a two-year lookback, adding a premium surcharge at 65 or 66.
Heirs change the answer. Roth money inherited under the 10-year rule is far better than traditional money, so a ladder can win on estate grounds even when it is a wash for you.

How Coastline models it — and the one mode to watch

Set a conversion window (start and end age) and either a fixed annual amount or a target bracket to fill. The projection makes the conversion before withdrawals each year, taxes it as ordinary income stacked on everything else, moves it into the Roth and its basis, shrinks the traditional balance, and recomputes the required distribution on the post-conversion balance. The conversion also flows into the ACA MAGI test and into the MAGI the IRMAA lookback reads two years later, so the trade-offs show up where they really happen.

Bracket-fill check (22% fill, 60–72): worst year $23,445 over the ceiling, age 60. Fixed-dollar conversions pin the bracket exactly.

Each rung waits its own five years in the projection: before 59½ only conversions at least five years old come out penalty-free.

Why Coastline's version is different

Most free calculators hand you a single headline number with the assumptions hidden. Coastline is built the opposite way:

Real tax math, not a flat rate. It applies federal and state income tax, long-term capital-gains rules, and account-by-account treatment (taxable, traditional, Roth) — in both your working years and retirement.
The whole journey. It models accumulation (saving and investing) and drawdown (spending it down), so you see how the plan connects end to end, not just one half.
The math is shown. Every figure has a click-through breakdown of how it was computed — a level of transparency even paid tools rarely expose.
All 50 states and DC, itemized deductions, IRMAA, ACA credits, 72(t) and student-loan forgiveness tax — modeled with the published rules. Each is the actual rule on inflation-indexed thresholds, applied in the year it lands, so a Roth conversion at 63 shows up as a Medicare surcharge at 65 and a forgiven loan balance shows up as that year’s tax bill.
Free, no signup. No account needed, no account-linking.

Educational, not tax advice. Figures: married filing jointly in a no-income-tax state, retiring at 50 with $500,000 taxable and $1,500,000 traditional, spending $50,000/yr plus $32,000/yr of health cover to 65, 6% nominal return, 3% inflation, Social Security of $40,000 claimed at 70, fixed conversions of $70,000/yr (today's dollars) from 50 through 72, projected to 92. Lifetime tax totals are deflated to today's dollars, because summing nominal tax across a 37-year plan overweights the late years. Conversions are irreversible — recharacterisation of a Roth conversion was repealed — so model before you convert, and confirm with a tax professional.

Run this with your real numbers

Set your own conversion window and amount, then compare lifetime tax, required distributions, and ending net worth with the ladder on and off.

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Common questions

How does a Roth conversion ladder work?

You convert part of a traditional 401(k) or IRA to a Roth each year and pay ordinary income tax on the amount converted. Five tax years later, each converted amount can be withdrawn penalty-free at any age. Repeated annually, the maturities form a ladder of accessible money — which is how retirees under 59½ reach funds that would otherwise carry a 10% penalty, while draining the balance that would later force required distributions.

How much should I convert each year?

Enough to use the low brackets your gap years hand you, without spilling into a higher one or across a means-tested threshold. In this page's projection, $70,000 a year from 50 converts $1,362,556 over 20 years and cuts lifetime tax by $108,575. Before 65 the binding constraint is often the ACA subsidy cliff rather than a tax bracket; from 63 it is the Medicare IRMAA thresholds on a two-year lookback.

Does a Roth conversion ladder reduce RMDs?

That is often its largest effect. Every dollar converted leaves the traditional account, so it is no longer in the balance that required minimum distributions are computed on. In this scenario the ladder empties the traditional account entirely — $0 at 73 versus $1,647,518 without it — so the $66,671 distribution that would have been forced at 75 becomes $0.

When is a Roth conversion ladder a bad idea?

When you convert at a higher rate than you would have paid later; when the conversion tax has to come out of the portfolio and cost you decades of compounding; when it pushes you over the ACA subsidy cliff in your pre-Medicare years; or when it triggers a Medicare IRMAA tier from 63 onwards. It is also unnecessary if you already have enough taxable money to bridge to 59½. The test to apply is whether lifetime tax AND ending net worth both improve — in this scenario they do, by $108,575 and $31,574 respectively, but that is not automatic.