Neither the backdoor Roth nor the mega backdoor Roth uses this adjustment - both are Cash Flow Priorities, covered in Backdoor and mega backdoor Roth. This page is about converting money you already hold in a Traditional account.

A Roth Conversion adjustment moves dollars from a Traditional retirement account into a Roth retirement account in a specified year. The converted amount is treated as fully taxable ordinary income in the conversion year, then sits in the Roth account where future growth is tax-free.

How the adjustment works

• Choose the source Traditional account and the destination Roth account.
• Enter the conversion amount in today's dollars.
• Set the year (one-time) or recurring window the conversion applies to.

In the conversion year, the engine adds the amount to ordinary income (which can push you into higher tax brackets and affect IRMAA, ACA subsidies, and Social Security taxability), debits the Traditional account, and credits the Roth account.

Manual adjustments vs the Roth Optimizer

The Roth Optimizer can recommend yearly conversion amounts based on goal mode (fill the 22% bracket, IRMAA-aware, etc.). Use the optimizer when you want guidance on how much to convert each year.

Reading the conversion rationale

In Analyze → Year-by-year data, every conversion that actually moved money shows as a purple Roth Conversion row. Click the row to expand a "Why this conversion?" panel that shows how that year's amount was sized. What you see depends on the mode the adjustment was set to:

• Fill to a bracket. Top of your target bracket, plus your deduction, minus the income you already had, equals the room left in the bracket.
• ACA limit. When the ACA subsidy cap is on and a healthcare adjustment is active, the panel adds a second block: the 400% federal-poverty-level ceiling, minus your income so far, minus the room reserved for this year's dividends and for the capital gains your spending withdrawals will realize, equals the room left under the ceiling. If the limit was deliberately skipped (your target bracket starts above the ceiling, or your income was already past it), the panel says so instead of showing the arithmetic.
• Fill to an IRMAA tier. The tier's income threshold, minus a small safety buffer, minus your income so far, minus the room reserved for the rest of this year's income, equals the room left below the tier. IRMAA tiers are cliffs, so the conversion holds back headroom for the taxable income the same year still has coming: this year's dividends, the taxable withdrawals that will fund your spending, and the capital gains those withdrawals realize. Each reserve gets its own line when it applies, and because that room is estimated before the year's withdrawals happen, your year-end income normally finishes a little further under the threshold than the target. Picking the top tier means there is no upper limit, so the amount you specified is converted.
• Fixed amount. No arithmetic. The panel says the amount is the one you set.

The last line names the binding constraint. The single thing that stopped the conversion from being larger: the top of your tax bracket, the ACA subsidy ceiling, your IRMAA tier ceiling, the balance available in the source account, or simply the amount you specified. If it says the source account balance, the plan wanted to convert more than the account held.

Years where no conversion happened have no purple row and no panel. The panel explains how a conversion was sized, not why one did not fire.

The Roth Conversion adjustment is where you record manual conversions. A specific dollar amount you intend to do in a specific year, regardless of optimizer suggestions. The two are independent: a plan can use the optimizer alone, manual conversions alone, or both layered together.