A Roth conversion means moving money from a traditional IRA (pre-tax) to a Roth IRA (post-tax). You pay income tax on the converted amount in the year of conversion. In exchange, the money grows tax-free forever, and there are no Required Minimum Distributions from the Roth account.

Why Convert at All?

The core argument for Roth conversions is simple: pay taxes at a known, controlled rate now rather than an unknown rate later. If you have a large traditional IRA, you'll eventually face Required Minimum Distributions starting at age 73 — mandatory annual withdrawals that are fully taxable as ordinary income. These can push you into higher brackets, trigger IRMAA Medicare surcharges, and increase Social Security taxation. A strategic conversion program in your 60s or early 70s can reduce this future tax burden significantly.

The Ideal Roth Conversion Window

The best time for conversions is typically after retirement but before RMDs begin — ages 59½ to 72. This is the window when:

• You have no employment income (lower tax bracket)
• Social Security hasn't started yet (no SS taxation)
• RMDs haven't forced income (you control the amount)
• You have years of tax-free growth ahead

How Much to Convert Each Year

The optimal conversion amount fills your current tax bracket without pushing into the next one. If you're in the 22% bracket (taxable income $47,150–$100,525 for 2025, single), and your current income is $60,000, you could convert up to ~$40,000 before hitting the 24% bracket. This "bracket filling" strategy converts as much as possible at the lowest available rate.

Roth Conversion Tax Considerations

The conversion amount is added to your ordinary income in the conversion year. You'll owe federal and state income tax on it. The critical rule: pay the tax from non-IRA funds. If you withdraw from the IRA itself to pay the tax, you lose the full compounding benefit of the conversion — and if you're under 59½, the tax withdrawal also triggers a 10% penalty.

When Conversions Don't Make Sense

  • Your current tax bracket is higher than your expected retirement bracket
  • You don't have outside funds to pay the tax (forcing IRA withdrawal for taxes negates most of the benefit)
  • You expect to leave the IRA to a low-income heir (they'll pay tax at their rate, potentially lower than yours)
  • You're in a high-income year due to a one-time event (stock sale, bonus)

Model your specific situation with the WealthSerene Roth Conversion Analyzer — it calculates the tax due now, projected RMD tax savings, and the net benefit over your planning horizon.