With the required minimum distribution (RMD) age now 73 under SECURE 2.0, many pre‑retirees and early retirees have a valuable window to convert traditional retirement account balances into tax‑free Roth assets. Done correctly, staged Roth conversions can shrink future taxable RMDs, reduce the portion of Social Security that’s taxed, and limit Medicare IRMAA surcharges. This guide walks retirement planning enthusiasts through a concrete, step‑by‑step approach you can model and implement with your advisor or tax preparer.

Why convert to Roth before RMDs begin?

Key benefits of converting traditional retirement savings (401(k) or IRA) to Roth IRA before RMDs start include:

  • Lower future RMDs. Roth IRAs are not subject to lifetime RMDs, so converting reduces the account base that will generate taxable RMDs after age 73.
  • Tax diversification. Roth balances provide tax‑free withdrawals in retirement to pair with taxable income from pension, 401(k)/IRA withdrawals and Social Security.
  • Heir efficiency. Roth IRAs pass tax‑favored to beneficiaries (subject to the 10‑year rule for many non‑spouse heirs), helping heirs avoid large taxable distributions.
  • Timing advantages. If you have years with lower taxable income—before you claim Social Security, or between leaving work and Medicare—those years can be attractive conversion windows at lower marginal tax rates.

Important constraints and rules to know

  • RMDs still must be taken in the year you first reach the RMD age (73 as of 2026) and every year after. You cannot convert the amount required for that year’s RMD into a Roth — you must take the RMD first.
  • Conversions create ordinary taxable income in the year of conversion. That can push you into higher tax brackets, increase the fraction of Social Security subject to tax, and trigger Medicare IRMAA surcharges.
  • Roth IRA 5‑year rule: each conversion starts its own five‑year clock for purposes of avoiding a 10% early‑distribution penalty on converted amounts withdrawn before age 59½. Plan liquidity accordingly.
  • Coordinate conversions with estimated tax payments or withholding so you don’t incur underpayment penalties.

Step‑by‑step plan: execute staged Roth conversions before RMDs

Step 1 — Inventory your accounts and income timeline

  1. Make a list of all pre‑tax retirement balances: employer 401(k), traditional IRA(s), SEP/SIMPLE IRAs, and any pension that’s paid as a lump sum option.
  2. Record current ages, planned Social Security claiming age, expected pension start dates (if any), and the year you will attain RMD age (73 as of 2026).
  3. Project non‑retirement income for each year until age 73: wages (if working), rental or business income, and any expected capital gains. These projections form your “conversion windows.”

Step 2 — Identify low‑income conversion windows

Ideal conversion years are those when your taxable income is unusually low: early retirement years before you claim Social Security or elect pension payments, a sabbatical year, or a year that includes deductible losses. For each candidate year estimate:

  • Taxable income before conversions
  • Marginal federal and state tax brackets
  • Social Security and Medicare enrollment timing

Target conversions that fill up a marginal tax bracket without pushing you into the next bracket or across IRMAA thresholds. Converting to “use” spare room in low brackets minimizes the tax cost of shifting dollars into tax‑free Roth balance.

Step 3 — Model the tax, Social Security and IRMAA effects

Use a spreadsheet or tax planning tool to run scenarios. Key interactions to model:

  • How additional taxable income from conversions increases provisional income used to determine Social Security taxation.
  • Whether conversion amounts push modified adjusted gross income (MAGI) above Medicare IRMAA thresholds, which trigger higher Part B/D premiums.
  • Cumulative long‑term effect: smaller traditional balances at RMD age reduce future yearly taxable RMDs.

Example approach: run two scenarios over the same horizon—(A) no conversions and (B) a series of staged conversions to reduce the traditional account by 50% by age 73—and compare lifetime projected federal tax and expected IRMAA surcharges.

Step 4 — Pick conversion amounts and schedule

Two practical tactics:

  • Bracket‑fill conversions: Convert exactly enough in a year to reach the top of a desired tax bracket. This keeps marginal tax on conversions predictable.
  • Fixed‑dollar ladder: Convert a consistent dollar amount each year to smooth income and taxation across time.

Example: if your pre‑conversion taxable income is $40,000 and the top of the 12% bracket is $55,000, converting $15,000 that year uses that bracket. In the next year your income may rise due to Social Security, so conversions should be smaller or paused.

Step 5 — Choose the technical path: in‑plan vs rollover conversions

  • 401(k) in‑plan Roth conversion (if your plan allows): you convert within the plan. Taxes are due in the year of conversion. Check plan rules for timing and vesting implications.
  • Roll traditional 401(k) to a traditional IRA first, then convert to a Roth IRA: this provides broader investment choices and is often more flexible for partial conversions.
  • Direct rollover to Roth IRA (Rollover conversion): execute a trustee‑to‑trustee transfer to avoid withholding issues.

Coordinate beneficiary designations during rollovers and conversions—Roth IRAs have different estate implications than traditional accounts.

Step 6 — Manage withholding, estimated taxes and cash flow

Conversions increase taxable income immediately. If you rely on withholding from IRA distributions to cover taxes, remember conversions do not automatically withhold unless you request it. Options:

  • Make quarterly estimated tax payments timed to conversion transactions.
  • Have taxes withheld from other sources (pension or wage withholding).
  • Budget cash outside retirement accounts to pay the conversion tax bill—using retirement funds to pay the conversion tax erodes the benefit.

Step 7 — Watch the 5‑year rule and withdrawal sequencing

If you’re younger than 59½ and anticipate needing converted amounts soon after conversion, remember each conversion has its own five‑year clock for avoiding the 10% early‑withdrawal penalty on converted principal. Plan conversions and your liquidity so you won’t be forced to withdraw converted amounts during the five‑year window.

Practical example (illustrative)

Maria, 62, leaves work in 2026. She has $600,000 in a traditional 401(k), expects $20,000/year in taxable income during early retirement, and plans to claim Social Security at 67. She wants to reduce future RMDs and avoid large IRMAA increases at Medicare enrollment age.

  • She inventories accounts and projects income to age 73.
  • She identifies tax years 62–66 as conversion windows before Social Security and Medicare.
  • She chooses bracket‑fill conversions of $30,000/year for five years—using her current low taxable base to stay in a lower marginal bracket.
  • She pays the conversion tax from savings outside retirement accounts and makes estimated payments quarterly.
  • By age 73 her traditional balance is materially reduced, lowering future RMDs and smoothing taxable income in later years.

This is illustrative; run numbers for your circumstances.

Coordination with Social Security and pensions

Two coordination points:

  • Timing of Social Security claiming affects your optimal conversion schedule. Starting Social Security increases provisional income and can make conversions more costly in the same year.
  • If you have a pension, model whether pension payments will begin before or after conversions. Start dates for pension income can create years with higher taxable income that you may want to avoid converting into.

When to pause or stop conversions

  • You may pause if conversions push you into a substantially higher tax bracket or across IRMAA thresholds.
  • Stop converting after RMDs begin for that year (you must take the RMD first); conversions can continue after taking the RMD, but the presence of required distributions complicates the math.
  • Consider pausing conversions in years when tax legislation or personal circumstances change materially (large capital gains, inheritance, starting a small business).

Working with advisors and tools

Roth conversion planning is a tax and cash‑flow puzzle. Use these resources:

  • A tax pro or CPA for year‑by‑year tax impact, state tax treatment and estimated payments.
  • A fee‑aware financial planner to run retirement income projections and compare “no‑conversion” vs conversion scenarios on lifetime taxes and portfolio longevity.
  • Tax planning software or spreadsheets that let you toggle conversion amounts, Social Security claiming ages and pension start dates.

Key takeaways

  • Start early. The years before RMDs (age 73 as of 2026) often present the best opportunities for cost‑effective Roth conversions.
  • Convert strategically. Use bracket‑fill or ladder approaches to smooth tax impact and avoid IRMAA cliffs.
  • Mind the rules. You must take any RMD for the year before converting those funds; watch the Roth 5‑year rule and conversion tax timing.
  • Coordinate. Plan conversions together with Social Security claiming, pension start dates and Medicare enrollment to preserve net retirement income.

Roth conversions are a powerful tool in the retirement planner’s toolbox — but they are not one‑size‑fits‑all. A deliberate, model‑based approach that maps conversions to specific low‑income windows can cut lifetime taxes, reduce taxable RMDs, and improve flexibility for you and your heirs.