Roth Conversions: When Paying Tax Early Is the Smartest Money You’ll Spend
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Most tax planning defers tax. The Roth conversion does the opposite on purpose: move money from a pre-tax IRA to a Roth, pay income tax on it now, and buy permanent tax-free growth, tax-free withdrawals, and freedom from required minimum distributions. Whether that trade wins comes down to one comparison: your tax rate today versus your rate when the money would otherwise come out.
The problem conversions solve
Large pre-tax balances are a deferred tax bill with a timer. At RMD age, withdrawals become mandatory and grow with the account — routinely pushing retirees into higher brackets, making more Social Security taxable, and triggering Medicare’s IRMAA surcharges. A $2 million IRA isn’t a $2 million asset; it’s a partnership with the IRS whose split gets renegotiated by future brackets. Conversions buy out the partner early, at rates you choose.
The golden windows
Conversions are a rate play, so the strategy is to convert in deliberately low-rate years:
The retirement gap years — after the paycheck stops, before Social Security and RMDs begin. Many retirees spend a few years in remarkably low brackets; those are the years the playbook was written for.
Business-loss or sabbatical years, a leave, early retirement, the year between jobs.
Market downturns — converting depressed shares moves more future recovery into the tax-free bucket for the same tax cost.
Bracket filling: the disciplined version converts just enough each year to fill the current bracket without spilling into the next — a repeatable annual exercise, not a one-time event.
The side effects to model (this is where DIY conversions go wrong)
Conversion income is real income. It can trigger IRMAA Medicare surcharges two years later, expose more investment income to NIIT, tax more Social Security, phase out credits, and — for pre-65 retirees — slash ACA premium subsidies, which can act like a 15–25% surtax on the conversion. A conversion that “fills the 22% bracket” but detonates two cliffs was not a 22% conversion. Model all of it, together, before December.
Execution rules
Conversions are irreversible — recharacterization of conversions ended years ago. Size carefully; convert in tranches.
Pay the tax from outside money, not from the converted funds — especially before 59½, where withheld amounts are also early distributions.
Mind the calendar: conversions count in the year executed (no April look-back), and each conversion starts its own 5-year clock for penalty-free access to that principal before 59½.
Withholding vs. estimates: conversion income usually needs an estimated payment or a withholding adjustment to avoid penalties.
Coordinate with heirs in mind: under the 10-year inherited-IRA rule, pre-tax balances dumped onto high-earning children are taxed at their peak rates. Conversions are often really a family-bracket arbitrage.
Done annually, in the right windows, with the cliffs modeled — the Roth conversion is the most valuable recurring decision in retirement tax planning. Done impulsively in a high-income year, it’s just prepaying tax at your worst rate. The difference is a projection.
Romanchuk CPA LLC is a fully virtual CPA firm serving individuals and business owners nationwide since 2014, with NJ/NY depth. Start with the 5-minute intake form at rfg.tax/start-here.
This article is general information, not tax advice for your specific situation. Figures adjust annually — verify current amounts.