Roth Conversion Basics — When, Why, and How Much

You take a portion of a Traditional IRA or 401(k), pay ordinary income tax on it this year, and move it into a Roth IRA. From that moment forward, that money grows tax-free, comes out tax-free in retirement, and passes tax-free to heirs (subject to the 10-year rule).

The trade is simple: pay tax now at a known rate, or pay tax later at an unknown — usually higher — rate.

The most powerful time to convert is typically the years between full retirement and the start of Required Minimum Distributions (currently age 73). During that window:

• Earned income often drops, lowering your tax bracket.
• Social Security may not yet be claimed.
• RMDs are not yet forcing taxable income on top.
• You have the most control over how much income you recognize.

Once RMDs begin, the IRS forces taxable withdrawals — and converting on top of those forced withdrawals is much more expensive.

The point isn't that conversions always win — it's that doing nothing is itself a tax decision, and usually the most expensive one.

• Large traditional IRA / 401(k) balances relative to total net worth.
• Retired but pre-RMD (typically ages 60–72).
• Expect equal or higher tax brackets later.
• Have non-IRA cash to pay the conversion tax.
• Want to reduce future IRMAA and widow risk.
• Want a tax-free legacy for heirs.

• You expect a much lower bracket later.
• You have to pay the conversion tax from the IRA itself.
• You're close to an IRMAA cliff and a conversion would trigger it.
• You plan to give most of the IRA to charity (QCDs may be better).