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Roth Conversion Ladder Calculator (2026)

The window between retirement and age 73 is your lowest-tax decade — use it to systematically convert traditional IRA money to Roth while filling brackets and avoiding IRMAA cliffs. This calculator models the Social Security torpedo effect and RMD trajectory to find your optimal conversion amount every year.

Just want a quick tax estimate for a single conversion? Roth Conversion Tax Calculator →

Roth Conversion Ladder Planner

Model your optimal annual conversion strategy, accounting for SS taxation and IRMAA cliffs.

Typically 15–25 years

$
$0$3,000,000

Pre-tax retirement accounts subject to RMDs

$
$0$1,000,000

Existing Roth (always accessible)

$
$0$2,000,000

Used to fund living expenses & conversion taxes

6%
1%12%

Applied to all accounts. Conservative: 5–6%; moderate: 7–8%.

$
$0$150,000

Pension, annuity, rental, part-time work

$
$0$60,000
$
$0$60,000
$
$0$50,000

Municipal bonds, etc. Counts toward IRMAA MAGI

Conversions stop when total taxable income reaches this ceiling

$
$20,000$300,000

Total gross annual spending. Covered by income → RMDs → bridge fund

20-Year Projection Summary

Total Roth converted

$934,497

over 5 active years

Total federal tax paid

$165,935

avg $33,187/yr on conversions

Final traditional IRA

$0

from $800,000 today

Final Roth IRA

$2,726,065

from $50,000 today

Final bridge fund

$0

depleted

Projected RMD at age 73

$64,391

if no conversions before 73

Bridge fund depletes before the planning horizon ends. Consider reducing the target bracket, increasing the bridge fund, or shortening the conversion window.

Stacked area shows how Traditional IRA shifts to Roth + bridge fund depletes over time.

This tool uses 2026 federal tax brackets and IRMAA thresholds. All calculations are estimates for planning purposes only — not tax or financial advice. Actual results will vary based on account performance, tax law changes, and individual circumstances. Consult a tax professional before acting.

How a Roth Conversion Ladder Works

A Roth conversion ladder is a multi-year strategy to systematically convert money from your traditional IRA (or 401k) into a Roth IRA — paying ordinary income taxes now, at a controlled rate, to get decades of tax-free growth. The window is the gap between retirement (when your income drops) and age 73 (when RMDs force distributions whether you want them or not).

The core tactic is "bracket filling": convert just enough each year to fill a target tax bracket ceiling — say, the top of the 22% bracket — without crossing into the next bracket. For most retirees, this means converting $50,000–$150,000 per year over a 10–15 year window.

The complications that make this tricky: (1) IRA withdrawals trigger Social Security taxation in a nonlinear way, effectively bumping your marginal rate 50–85% above the statutory rate (the "tax torpedo"). (2) Your MAGI, which includes Roth conversions, determines IRMAA Medicare surcharges two years later — crossing a cliff by $1 can cost thousands per year. (3) Converted funds must season for 5 years before the earnings are penalty-free (the "5-year rule"). This calculator models all three effects.

The strategy pays off primarily when: (a) you're currently in a lower bracket than you expect to be in the future due to RMDs, (b) you want to leave tax-free Roth assets to heirs, or (c) you want to reduce your lifetime Medicare premiums by managing future MAGI.

This calculator shows a recommended conversion amount for each year, the tax cost, and how your account balances evolve over your planning horizon. Adjust the strategy inputs to find the approach that makes sense for your situation.

5 Tips to Maximize Your Conversion Window

1

Start before RMDs begin

The conversion window closes at 73 when RMDs begin. The earlier you start (even at 60–65), the lower your required conversion amount each year and the more time your Roth has to grow tax-free.

2

Watch the IRMAA cliffs

Your conversion in 2026 determines your Medicare premium in 2028. Enable the IRMAA cap to ensure conversions never cross a tier boundary. Single: $109k / $137k / $171k / $205k / $500k. MFJ: $218k / $274k / $342k / $410k / $750k.

3

Account for the Social Security torpedo

If you collect SS, large conversions can push more of your SS into taxation — effectively raising your marginal rate well above the bracket rate. This calculator models the SS torpedo effect when computing your conversion ceiling.

4

Use the bridge fund strategically

Conversion taxes come due in April. Fund them from your taxable brokerage, not from the Roth itself. Selling appreciated taxable assets (at potentially favorable long-term capital gains rates) to fund conversion taxes is often more efficient than pulling from the Roth.

5

Consider QCDs at 70½

Qualified Charitable Distributions let you direct up to $105,000/year from your IRA to charity without it counting as taxable income. QCDs can satisfy your RMD obligation while keeping your MAGI low — creating more room for additional Roth conversions.

Who Benefits Most from a Roth Conversion Ladder?

Not everyone has a compelling case for systematic Roth conversions. The strategy delivers the most value in specific situations — and understanding which category you fall into is the first step.

Early retirees (ages 40–55): The FIRE community has the longest runway. Retiring at 45 means potentially 28 years before RMDs begin at 73 — enough time to systematically drain a large traditional IRA at low rates. For this group, the 5-year seasoning rule is the dominant constraint: converted funds can't be accessed penalty-free until 5 years after conversion (if under age 59½). Starting the ladder early — ideally the first year after retirement — ensures the first rungs are accessible right when the bridge fund starts running thin. Early retirees also tend to have low enough income to benefit substantially from ACA premium tax credits, which can complicate conversion sizing (more on that below).
Pre-retirees and recent retirees (ages 55–65): This is the sweet spot. Income just dropped — earned wages stopped, Social Security hasn't started, RMDs are still 8–18 years away. The window is wide open. A couple who retires at 60 with $1.2M in a traditional IRA and modest pension income might find themselves in the 12% bracket for the first time in decades. Converting $80,000–$120,000 per year during this window, for 7–10 years, can dramatically reduce the balance that will eventually be subject to forced distributions.
People with large traditional balances ($500k+): The RMD math is punishing at scale. A $1 million traditional IRA at age 73 generates a first-year RMD of roughly $37,700 — before a single dollar of Social Security or other income. A $2 million balance produces ~$75,500. Add SS, and you're well into the 22%–24% bracket before any voluntary spending. Converting now, even at 22%, is often cheaper than paying 22%+ on RMDs that compound the problem year after year. The larger the traditional balance, the more urgent the conversion window.
People who delayed Social Security: Delaying SS to age 70 produces a 32% larger monthly benefit than claiming at 67 — but a larger benefit means a wider torpedo zone. When a $42,000/year SS benefit becomes 85% taxable, the effective marginal rate on IRA withdrawals spikes to 40.7%. Converting traditional IRA money before claiming SS sidesteps this trap entirely. The conversion happens at the statutory bracket rate; withdrawals after SS begins are subject to the amplified torpedo rate.

The strategy makes less sense if: you're already in the 24%+ bracket with no expected income drop, your traditional IRA balance is small (under $100,000) and won't generate significant RMDs, or you need the money immediately and can't sustain the tax cost of conversions. In those cases, the math favors letting the money grow and paying taxes later — or on withdrawal.

The Bridge Fund Strategy: Funding Your First 5 Years

A bridge fund is the pool of accessible money you live on during the years before Roth conversion rungs mature. It's what lets you execute the ladder without touching converted funds before the 5-year clock runs out.

Bridge fund sources include: taxable brokerage accounts (the most tax-efficient — long-term capital gains rates often 0% in low-income years), direct Roth IRA contributions (always accessible at any age, never subject to the 5-year rule), savings accounts, HSA reimbursements for past medical expenses, and part-time or consulting income. These are not interchangeable — taxable brokerage is usually preferable because selling appreciated assets in a low-income year can trigger zero capital gains tax.

The rule of thumb: you need at least 5 years of living expenses in bridge funds before starting the ladder. In practice, this means if your annual spending is $60,000 and your only income is a $15,000 pension, you need roughly $225,000 in accessible savings (5 × $45,000 spending gap) to comfortably execute the strategy. If your bridge is shorter than 5 years, you'll either need to reduce conversion amounts, accept some penalties, or supplement with 72(t) SEPP distributions.

Alternatives for those without adequate bridge funds: 72(t) SEPP (Substantially Equal Periodic Payments) allows penalty-free IRA distributions before 59½ but requires a rigid payment schedule for at least 5 years or until age 59½ — any modification triggers retroactive 10% penalties on all prior distributions. The Rule of 55 allows penalty-free access to a current employer's 401(k) if you separate from service at or after age 55, but this doesn't apply to IRAs. Part-time or consulting income can supplement both the bridge and the conversion budget.

The Roth Conversion Ladder Calculator tracks your bridge fund balance year by year and shows when funds are projected to run low — which is often the binding constraint that limits how aggressively you can convert.

Roth Conversion Ladder Before RMDs: Why Timing Matters

Required Minimum Distributions start at age 73 for anyone born before 1960, and at age 75 for those born in 1960 or later. Once RMDs begin, they're mandatory — and they eat bracket space before any voluntary income decisions can be made.

To see why this matters, consider a retiree at 73 with $1.2 million in a traditional IRA. The IRS Uniform Lifetime Table divisor at 73 is 26.5, meaning the first RMD is approximately $45,300. Add $30,000 in Social Security, and income before any optional withdrawals is already $75,300. For a single filer in 2026, the standard deduction is $16,100 and the senior deduction adds another $6,000 — leaving roughly $53,200 of taxable income. That's $3,000 from the top of the 12% bracket ceiling ($50,400 for single filers). There's almost no room to layer Roth conversions on top without spilling into 22%.

The ideal conversion window is the period between retirement (when earned income drops) and age 73 (when forced distributions begin). Every year spent converting during this window is a year that reduces the traditional balance — and therefore the future RMD — at a rate you control. Every year you delay is a year of compounding that increases the future RMD obligation.

Roth conversions are still possible after 73 — but with an important constraint: you must satisfy your RMD for the year before converting any additional amounts. RMDs cannot be rolled over or converted; they must be distributed and taxed. Any conversion is layered on top of the RMD, compressing your bracket space further. The math still works in some cases — particularly for people with large balances who want to pass Roth assets to heirs — but the break-even period is shorter and the benefit is smaller.

The calculator models this explicitly: it shows your projected RMD by age with and without a conversion strategy, so you can see exactly how much the ladder reduces your forced distributions in your 70s and 80s.

Check your IRMAA exposure: Roth conversions increase your MAGI and can push you over an IRMAA Medicare surcharge cliff two years later. Use the Medicare IRMAA Calculator to see exactly how much headroom you have before the next cliff.

Watch for the SS torpedo: Large IRA withdrawals or Roth conversions can trigger 85% SS taxation, pushing your effective marginal rate to 40%+. See the Social Security Tax Torpedo Calculator for a detailed marginal rate breakdown.

Plan your in-retirement withdrawal sequence: Once conversions are complete, the order you draw from Traditional, Roth, and taxable accounts matters just as much. Use the Withdrawal Order Optimizer to compare strategies and see the lifetime tax difference.

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Read: The Roth Conversion Ladder Strategy →

Frequently Asked Questions

A Roth conversion ladder converts traditional IRA money into a Roth IRA over several years, paying taxes now at a controlled rate. Retirees do this to reduce future Required Minimum Distributions (which can push them into higher brackets), to pass on tax-free assets to heirs, and to manage Medicare IRMAA surcharges — which are based on income from two years prior.
The ideal window is between early retirement (when earned income drops) and age 73 (when RMDs begin). During this window, your taxable income is often at its lowest, making conversions cheapest. If you're collecting Social Security, be aware that large conversions can push more SS income into taxation — the calculator models this effect.
Each Roth conversion starts its own 5-year clock. Converted amounts (not earnings) can always be withdrawn penalty-free after age 59½. But earnings on converted amounts must wait 5 years from the conversion date before they can be withdrawn tax-free. If you're 59½ or older, the penalty concern is mostly moot — the main 5-year rule that matters is on earnings.
IRMAA is calculated on your MAGI from two years prior. Roth conversions are treated as ordinary income and count toward MAGI. A large conversion in Year 1 shows up as a higher Medicare premium in Year 3. The "cap at IRMAA cliff" feature in this calculator limits your conversion each year to avoid crossing the next IRMAA tier boundary, which can save thousands in Medicare premiums.
If you're receiving Social Security, large IRA withdrawals or Roth conversions can trigger more of your SS benefit to be taxable (up to 85%). This can effectively make your marginal tax rate 40–50% higher than the bracket rate suggests — the "torpedo" effect. This calculator accounts for SS taxation when finding your optimal conversion amount.
Required Minimum Distributions are mandatory annual withdrawals from traditional IRAs starting at age 73, calculated as your account balance divided by an IRS life-expectancy factor. If your traditional IRA grows large, RMDs can force substantial taxable income in your 70s and 80s — potentially at higher rates than conversions done earlier. Converting now at a known rate can be far cheaper than paying higher rates on forced RMDs later.
The bridge fund is your taxable brokerage or savings account used for living expenses during the conversion window. Since Roth conversions increase your taxable income without providing spendable cash, you need another source for living costs while you convert. The bridge fund covers the gap between your income (pension, Social Security, RMDs) and your spending needs, plus the tax bill on conversions. When the bridge fund is depleted, the strategy becomes harder to sustain.
People with large traditional IRA or 401(k) balances ($500,000+) who are in or approaching a low-income window before Social Security and RMDs begin. Early retirees (FIRE practitioners aged 40–55) and people aged 55–65 who have recently stopped working are the ideal candidates — they have the longest runway to convert at low rates and the most to lose from future forced distributions. People who delayed Social Security also benefit significantly because converting before claiming SS sidesteps the tax torpedo zone entirely.
Bridge funds are accessible money — taxable brokerage accounts, savings, direct Roth IRA contributions (not conversions) — that you live on during the 5-year seasoning period before converted amounts become available penalty-free for those under age 59½. The rule of thumb is 5 years of living expenses in bridge funds before starting the ladder. Without adequate bridge funds, you can't execute conversions without either paying penalties or drawing down the Roth itself, which defeats the purpose.
Yes, but you must take your Required Minimum Distribution first — RMDs cannot be converted. After satisfying the RMD for the year, you can convert additional traditional IRA amounts. However, the math is less favorable: RMDs already consume bracket space, leaving less room to layer conversions without spilling into higher rates. Conversions after 73 can still make sense for reducing the future RMD trajectory or leaving Roth assets to heirs, but the break-even period is shorter.
A single Roth conversion is a one-time move of a specific dollar amount from a traditional IRA to a Roth IRA. A Roth conversion ladder is a multi-year strategy of repeated annual conversions designed to systematically fill low tax brackets and build a stream of accessible, penalty-free Roth funds — particularly for early retirees who need access before age 59½. The 'ladder' metaphor refers to the sequential rungs of conversions, each with its own 5-year clock, that collectively create a sustainable annual cash flow from Roth assets.
It depends on your future RMD trajectory and expected future rates. If your projected RMDs would push you into the 24%+ bracket, converting to the top of 22% now is a clear win. If your RMDs are modest, filling to the top of 12% may be sufficient. Use the calculator to see how account balances change across scenarios — a larger annual conversion depletes the traditional IRA faster and reduces future RMDs, but costs more tax today.