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.

$61,281 less lifetime tax — 15 rungs from 55, in today's dollars

Converting $50,000/yr from age 55 moves $745,405 into the Roth over 15 years, at a cost of $54,209 in conversion tax. Total lifetime tax falls from $148,549 to $87,268, required distributions at 75 drop from $39,400 to $0, and the plan ends at 92 with $985,641 instead of $962,460.

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 — which for most early retirees means starting before the taxable account runs dry, not after.
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 55 to 69 are spent filling low brackets on purpose while the taxable account funds 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 55 with $1,000,000 in a traditional 401(k), $500,000 in a taxable account, spending $70,000/yr, Social Security at 70. Converting $50,000/yr in today's dollars from 55, all figures deflated to today's dollars:

Roth conversion ladder from 55 → the traditional balance drains and the RMD disappears
Age	Converted	Traditional balance	Roth balance	RMD without the ladder
55	$50,000	$950,000	$50,000	—
60	$50,000	$831,653	$322,712	—
65	$50,000	$412,810	$637,521	—
75	—	$0	$877,430	$39,400
80	—	$0	$904,758	$44,258

The traditional account is empty by 70: $0 at 73 with the ladder versus $935,908 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 $39,400 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 $61,281 lower in today's dollars, and real net worth at 92 is $23,181 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 $54,209 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 one limitation to know

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.

The limitation: the bracket-fill mode sizes each conversion from an estimate of the year's other ordinary income. Once the taxable account is exhausted and the traditional account has to fund both the spending and the conversion, that estimate runs low and the fill overshoots its target. In a measured 22%-bracket fill run from 60 to 72, the worst year (age 63) produced about $287,738 of taxable income against an indexed ceiling of roughly $231,002 — an overshoot of $56,736, well into the next bracket up. Use fixed-dollar conversions (as every figure on this page does) when you need the bracket respected exactly, and read the year-by-year table rather than trusting the sizer.

The five-year clock is also a simplification: the projection treats conversions as the ladder strategy and assumes each rung's waiting period is satisfied before it is spent. If you plan to spend converted money sooner than five years after converting it, that assumption is doing work you should check by hand.

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.
US and Canada. It natively handles Canadian plans (RRSP, TFSA, CPP, OAS) alongside US accounts, which most calculators ignore.
Free, no signup. No account, no email, no account-linking. Your inputs run the projection and are then discarded.

Educational, not tax advice. Figures: married filing jointly in a no-income-tax state, retiring at 55 with $500,000 taxable and $1,000,000 traditional, spending $70,000/yr, 6% nominal return, 3% inflation, Social Security of $40,000 claimed at 70, fixed conversions of $50,000/yr (today's dollars) from 55 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, $50,000 a year from 55 converts $745,405 over 15 years and cuts lifetime tax by $61,281. 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 $935,908 without it — so the $39,400 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 $61,281 and $23,181 respectively, but that is not automatic.