How does aggregating IRAs work when I need to take RMDs from several accounts?

The IRS lets you total the required minimum distributions from all your Traditional, SEP, and SIMPLE IRAs and then take the entire combined amount from any one or more of them, in whatever mix you choose. So if you have three IRAs, you calculate each account's RMD, add them up, and can satisfy the whole obligation by withdrawing from a single account. This flexibility does not extend across account types: IRA RMDs and 401(k) RMDs can't be combined, and each 401(k) must generally pay its own RMD separately. Inherited IRAs also follow their own aggregation rules. This lets you leave your best-performing IRA untouched while draining another. Confirm the aggregation rules at irs.gov.