A Roth conversion makes sense when the marginal federal and state tax rate you would pay today on the converted amount is lower than the marginal rate you expect to face when the funds are withdrawn — typically post-RMD age 73, post-pension start, or after the death of one spouse. The decision is a forward-looking bracket comparison, and the conversion is one of the few wealth-planning moves with effectively no take-back: once executed, it cannot be reversed.
The break-even math
A Roth conversion accelerates a tax payment that would otherwise occur at withdrawal. The break-even is the future tax rate that would equal the cost of paying today. Two formal cases:
- Future rate > current rate: convert. The dollar value of the conversion grows tax-free; future withdrawals avoid the higher rate.
- Future rate < current rate: don't convert. The pre-tax position is more efficient because future withdrawals at a lower rate are cheaper than today's conversion at a higher rate.
- Future rate ≈ current rate: indifferent on the rate alone, but conversion often still wins because of two structural advantages — (a) Roth IRAs have no required minimum distributions for the original owner, and (b) inherited Roth IRAs can extend tax-free growth for up to ten years under the SECURE Act, Section 401(a)(9)(H).
Five windows when conversion is most efficient
- Job change between roles or industries. A short period of zero or reduced earned income drops the marginal rate. A planner can model the bracket-fill conversion amount that uses up the 12% or 22% federal bracket without spilling into the next.
- Early retirement, before Social Security and RMDs. The window between retirement (often 60–65) and RMD age (73 under SECURE 2.0, Section 107) is the highest-leverage Roth conversion period for most households. Earned income has stopped; Social Security may be delayed; RMDs have not yet started. The marginal rate falls.
- Business loss year. Pass-through entity losses, partnership K-1 losses, or a large depreciation deduction can collapse the current-year marginal rate. Conversions executed in the same year capture the rate drop.
- Large charitable year. Bunched charitable contributions — particularly via a donor-advised fund or qualified charitable distribution — reduce taxable income enough to lower the marginal rate on a conversion.
- Market drawdown. Converting after a 15–25% equity drawdown lets the same number of shares move into the Roth at a lower current value, with future recovery growing tax-free. The IRS values the conversion at the date-of-conversion fair market value (IRC §408A(d)(3)).
The IRMAA and Social Security ripple effects
A Roth conversion raises modified adjusted gross income (MAGI) for the year of conversion. Two cost structures key off MAGI:
- IRMAA (Income-Related Monthly Adjustment Amount) raises Medicare Part B and Part D premiums based on MAGI from two years prior. A conversion at age 63 raises premiums at age 65. The 2026 tiers begin at $103,000 MAGI for individuals and $206,000 for couples. The marginal cost of crossing a tier is several hundred dollars per month per person.
- Social Security taxation. Up to 85% of Social Security benefits become taxable once combined income exceeds $44,000 (married filing jointly) — a low threshold. A large conversion executed while collecting Social Security can pull most of the benefit into taxable territory.
The implication: conversions executed before Social Security starts and before the IRMAA two-year look-back covers the conversion year are structurally more efficient.
Georgia-specific considerations
Georgia's retirement-income exclusion (O.C.G.A. § 48-7-27) exempts up to $35,000 per person aged 62–64 and up to $65,000 per person aged 65+ of qualified retirement income from Georgia state income tax. The exclusion includes pension income, IRA distributions, Social Security, and capital gains up to the cap. A Roth conversion itself is taxable Georgia income in the year of conversion — but future Roth withdrawals are not.
For a Cherokee County household planning a multi-year conversion ladder, the sequencing question becomes: convert pre-exclusion (under 62) at full state rates, or convert post-exclusion (65+) where the first $65,000 per person of pre-tax IRA distributions is exempt anyway? In practice, the early-retirement window between 62–73 captures most of the federal-bracket arbitrage; the state-exclusion question shifts the marginal calculation by ~5.75%.
When NOT to convert
- The conversion tax would push you into the 32% or 37% federal bracket.
- You would need to use the IRA itself to pay the tax (defeats the benefit).
- You will move to a lower-tax state in the next five years (e.g., Florida from Georgia).
- A large charitable bequest will route around the pre-tax IRA via qualified charitable distribution at age 70½+ anyway.
- Your heirs are in much lower brackets than you are.
A clean conversion strategy is usually a multi-year ladder rather than a single large event — convert a calibrated amount each year that fills the lower bracket without spilling into the next. The Tax & Accounting practice models this sequence; the Wealth Management practice handles the cash-flow side of the tax payment. Schedule a Conversation to walk through last year's return and project a five-year ladder.
Observations are shared. Decisions stay yours. Securities offered through LPL Financial, Member FINRA/SIPC.