How much should you convert to Roth each year?

Short answer: Convert only the amount supported by a multi-year comparison of today’s tax cost against the expected future benefit. “Convert to the top of the bracket” can be a useful scenario, but it should not be treated as the answer by itself.

A conversion moves money from a tax-deferred account to a Roth account. Untaxed amounts converted are generally included in income for that year. The decision is therefore about purchasing future tax flexibility at a known current cost—and deciding how much flexibility is worth buying this year.

Begin with income before the conversion

First estimate taxable income and modified adjusted gross income without any conversion. Include pensions, wages, taxable Social Security benefits, portfolio income, realized gains, business income, required distributions, and other expected items. Then estimate deductions and any large one-time events.

This baseline shows how much room may exist before another marginal tax rate or planning threshold is reached. It also prevents the conversion from being modeled as though it were the household’s only source of income.

Why “fill the bracket” is incomplete

Federal income-tax brackets are important, but a conversion can affect more than the ordinary-income rate. Depending on the household, additional income may change the taxable portion of Social Security, interact with capital-gain taxation, influence Medicare IRMAA, affect income-based health-insurance assistance before Medicare, or create a different state-tax result.

These interactions do not mean conversions should be avoided. They mean the relevant marginal cost can be different from the tax bracket printed in a table. A projection should show the total change in tax and other modeled costs for each additional conversion increment.

Compare several amounts—not one guess

A practical review might compare no conversion with several partial-conversion scenarios. Each scenario should show current tax, projected Medicare effects when applicable, future traditional and Roth balances, expected RMDs, and the estimated after-tax value available for retirement or heirs.

Small increments can make the tradeoffs visible. If an additional dollar of conversion begins creating substantially higher connected costs, the household can see where that occurs and decide whether the long-term benefit still justifies it.

Include the source of the tax payment

A conversion is usually more compelling when the tax can be paid from funds outside the retirement account without undermining emergency reserves or near-term spending. Withholding tax from the converted retirement assets leaves less money in the Roth account and can create additional complications, particularly for someone below age 59½.

The analysis should therefore identify both the conversion amount and the tax-funding source. Liquidity, estimated-tax requirements, and portfolio consequences belong in the implementation plan.

Model the future household—not only today’s return

Future tax rates are uncertain, but future circumstances can still be modeled. Consider when RMDs may begin, whether a pension or Social Security benefit will start later, whether one spouse is likely to file as a single taxpayer after the first death, and how beneficiaries may be required to distribute inherited retirement accounts.

A series of measured annual conversions may provide more control than one very large conversion. It also allows the plan to be updated as tax law, markets, income, deductions, health costs, and personal priorities change.

The annual review framework

1. Update the current-year tax projection before the conversion.
2. Identify upcoming income events, deductions, gains, and charitable plans.
3. Model several conversion amounts and their connected effects.
4. Compare the lifetime and survivor outcomes—not merely the current refund or balance due.
5. Confirm adequate cash for taxes and near-term spending.
6. Coordinate the selected amount with the qualified tax professional before the year-end deadline.

To understand why timing before required distributions can matter, read Why the years before RMDs can create a Roth-conversion window or explore our RMD and Roth conversion planning process.