With multiple traditional IRAs, the RMD is calculated separately for each account but can be aggregated and satisfied from any one IRA or combination of them. The catch: you have to satisfy the total aggregate RMD across all your IRAs before converting from any of them, not just the specific account the RMD happened to be pulled from. Converting from IRA A while the RMD was withdrawn from IRA B doesn't clear IRA A for conversion unless the household's full aggregate RMD has already been met.

401(k) and 403(b) plans work differently and generally can't be aggregated with IRAs or with each other across separate employers. If you're rolling a 401(k) into an IRA in a year you're subject to RMDs on that plan, the RMD for that specific 401(k) has to come out first, in cash, and it cannot be rolled into the IRA either. Multiple 403(b) accounts can typically be aggregated with each other, but not with a 401(k) or an IRA.

Qualified charitable distributions interact with this ordering too, and in a household's favor. A QCD counts toward satisfying the year's RMD, so many households satisfy part or all of the RMD through a QCD first, then convert whatever remains above the RMD amount to a Roth, accomplishing a charitable goal and a conversion goal in the same year without conflict.

Getting the order wrong has a real, ongoing cost, not just a one-time correction. An improperly converted RMD is treated as an excess Roth contribution, which carries a 6% excise tax for every year it remains in the account uncorrected. The fix is to withdraw the excess amount, plus any earnings it generated, before the tax filing deadline for that year. Miss that window, and the 6% tax keeps applying annually until it's fixed.

The practical fix most households use is simply sequencing the two transactions deliberately rather than trying to net them against each other. Take the full RMD early in the year, before any conversion activity starts, and treat the conversion decision as a separate, later step once the RMD is confirmed satisfied and the rest of the year's tax picture is clearer.

A quick example makes the order concrete. Say a $1.2 million traditional IRA generates a $48,000 RMD for the year, and the household also wants to convert $150,000 to fill out the 24% bracket before it expires. The correct sequence is: withdraw the $48,000 RMD first, in cash or in kind, report it as ordinary income, and only then convert up to $150,000 of the remaining balance. If the custodian processes a $150,000 conversion first and the household plans to take the $48,000 RMD later in the year from the same account, the IRS treats the first $48,000 of that conversion as the RMD, not eligible for conversion, and the household now has a $48,000 excess Roth contribution to unwind.

Inherited IRAs add a wrinkle worth knowing rather than assuming. A non-spouse beneficiary generally cannot convert an inherited traditional IRA to a Roth at all, regardless of RMD ordering, since a Roth conversion of an inherited account is only available to a spouse beneficiary who elects to treat the IRA as their own, which turns it into that spouse's own IRA rather than a beneficiary account. A non-spouse beneficiary who wants Roth exposure has to build it through their own separate IRA contributions or conversions, not through the inherited account itself.

If you're subject to RMDs and doing Roth conversions in the same year, build the process around taking the RMD first and converting only the amount above it, don't try to net the two together or assume a large conversion automatically covers the requirement.

If you have multiple IRAs, confirm the total aggregate RMD across all of them is satisfied before converting from any single IRA, not just the one the RMD happened to come from.

Talk to your custodian before year-end about how they sequence RMD and conversion requests on their end, some process requests in the order received rather than automatically applying RMD-first logic, which puts the responsibility on you to request them in the right order.

Build this into your calendar rather than your memory. A simple, repeatable habit, confirm the year's aggregate RMD across every account, satisfy it first, then submit conversion requests, removes the guesswork and the risk of an expensive ordering mistake in any year you're doing both at once.

• Assuming a large Roth conversion automatically covers the RMD because the money came out of the account anyway.
• Converting from one IRA while taking the RMD from a different IRA without confirming the total aggregate RMD across all IRAs has been met.
• Forgetting that 401(k) and 403(b) RMDs generally can't be aggregated with IRA RMDs or with each other across different employers.
• Not correcting an improperly converted RMD before the tax filing deadline, letting the 6% excise tax accumulate year after year.