RMD Aggregation Rules — IRA vs. 403(b) vs. 401(k)
Learn which RMDs can be aggregated and which must be taken separately across IRAs, 403(b)s, and 401(k)s to avoid penalties.
Published on 9/19/2025
Quick Rules
- IRAs (including SEP/SIMPLE) can be aggregated and taken from any one or more IRAs
- 403(b)s can be aggregated with other 403(b)s (legacy rule)
- 401(k) RMDs must be taken separately from each plan
Why It Matters
Incorrect aggregation can cause missed RMDs and excise taxes. Map accounts, owners, and plan types annually.
Best Practices
- Keep an “RMD map” listing each account type and custodian
- Use the prior 12/31 balances and age‑based factors from the correct table
- Document withdrawals and confirmations from custodians
Example: What Can I Aggregate?
Marie has 3 IRAs and 2 old 401(k)s. She can aggregate the 3 IRAs and take the total IRA RMD from one IRA if she prefers. She must calculate and withdraw each 401(k) RMD separately from the plan holding that balance.
Tools to Use
RMD aggregationIRA RMD403b RMD401k RMDpenalties