RMDs: Which Accounts Can Be Combined, and Which Cannot
Someone with four accounts computes the right total, takes it all from the largest one because that is simplest, and has still failed to satisfy the requirement. The reason is aggregation: the rules about which accounts may be pooled differ by account type, and the total being correct does not save a distribution taken from the wrong place.
- IRAs:: Compute per account, take the total from whichever you like. SEP and SIMPLE IRAs join this pool.
- 401(k) and similar:: Each plan calculates and distributes separately. No pooling, in either direction.
- 403(b)s:: Aggregate with each other, but not with IRAs and not with 401(k)s.
- Inherited accounts:: Stand entirely alone. An inherited IRA's requirement cannot be met from your own IRA, or the reverse.
Where the AI summary above gets this wrong
"Add up your retirement accounts, take the required percentage, and you have met your RMD."
That's surface-true. Here's what it misses:
- The correct total from the wrong account still fails — The requirement is per-account before it is per-person. Taking a whole year's total from a single 401(k) leaves the other 401(k)'s requirement unmet, and the shortfall penalty attaches to that account regardless of how much left the first one.
- Account types pool in three separate groups, not one — IRAs pool with IRAs. 403(b)s pool with 403(b)s. Employer plans like 401(k)s pool with nothing at all. Three separate calculations, and money moved between the groups does not count against the other group's requirement.
- Inherited accounts are a fourth silo — An inherited IRA carries its own requirement, on its own schedule, and it cannot be satisfied out of your own IRA — nor can yours be satisfied out of it. Someone who inherited an account and holds one of their own has at minimum two independent obligations each year.
01 Why aggregation is the part that goes wrong
The required minimum distribution is computed account by account: each account's prior year-end balance, divided by a life expectancy divisor. That part is arithmetic and most people get it right.
What comes next is the question of where the money may actually be taken from, and the answer depends on the account type. Some types allow the separately computed amounts to be pooled and satisfied from any account in the group. Others require each account to distribute its own amount.
The failure mode is a person who has computed a correct total, withdrawn a correct total, and still owes a penalty, because the withdrawal came from a group that was not permitted to cover the shortfall. The general RMD strategy question — how to reduce these over time — only matters once the mechanics are right.
Source: Publication 590-B
02 The three groups, and the fourth that stands alone
Traditional IRAs aggregate. Compute the requirement for each, add them, and take the total from any one IRA or any combination. SEP and SIMPLE IRAs belong to this group. This is the flexibility that makes an IRA the natural home for a qualified charitable distribution, which can only be made from an IRA.
Employer plans — 401(k), and governmental 457(b) — do not aggregate. Each plan computes its own requirement and each must distribute it. Two old 401(k)s from two former employers are two separate obligations.
403(b) plans aggregate with other 403(b) plans and with nothing else. Inherited accounts are separate from everything including each other, on their own schedules, and can never be combined with an account you own.
Shows: the combined required distribution, split between the IRA side, which may be taken from any one IRA, and the employer-plan side, which must come from each plan separately. Ignores: inherited accounts, which follow their own rules, Roth accounts, the still-working exception, and any spousal-beneficiary adjustment to the divisor.
Source: Retirement plan and IRA required minimum distributions FAQs
03 What to do about it
The practical answer for most people is consolidation, done before the first required distribution rather than during it. Old employer plans rolled into a single IRA collapse several independent obligations into one pooled calculation, and the annual administrative work drops to a single withdrawal decision.
Two things argue against consolidating everything. A governmental 457(b) loses its early-access advantage when rolled out, and a 401(k) at a current employer may qualify for the still-working exception that an IRA does not offer. Neither is a reason to leave four dormant accounts scattered.
Whatever the structure, write down each year which group each account belongs to and what each group requires. Three lines on paper is the whole defence against the most expensive clerical error in retirement.
This is the least interesting rule in retirement and one of the most expensive to get wrong, because the person who gets it wrong is invariably being careful. They did the arithmetic, they took the money out, and the penalty arrives anyway. If you have accounts in more than one of these groups, the fix is almost always to consolidate before the first distribution year rather than to administer the complexity for the next twenty. Do it while it is a housekeeping task and not a deadline.
FAQ
Can I take my whole RMD from one account?
From one IRA, yes, if the requirement being satisfied is the IRA group's total. From one 401(k), no — each employer plan must distribute its own amount, and a large withdrawal from one does not cover another.
Do 401(k) and IRA required distributions combine?
No. They are separate groups. An IRA withdrawal does not satisfy a 401(k)'s requirement and a 401(k) withdrawal does not satisfy an IRA's, however large either one is.
Does an inherited IRA aggregate with my own IRA?
No. Inherited accounts stand alone, on their own schedule. If you hold both, you have at least two independent requirements to satisfy each year.
Sources
Regulator references
- Retirement plan and IRA required minimum distributions FAQs · Internal Revenue Service · 2026The aggregation rules: which account types may be combined and which may not.Last verified: 2026-09-07
- Retirement topics: required minimum distributions · Internal Revenue Service · 2026Which accounts are subject to RMDs and when the first one is due.Last verified: 2026-09-07
- Publication 590-B · Internal Revenue Service · 2026The life expectancy tables that supply the divisor.Last verified: 2026-09-07
Calculator unit tests · the assertions this page's worked example is checked against, and their last result
Changelog
- 2026-09-07 — initial publish (new format)
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Jordan Reeves
Founder of Talk Through Wealth. A software engineer for over a decade before turning to retirement planning, Jordan built the projection engine after watching family members get fragmented, country-by-country advice that never reconciled. He writes about retirement the way the engine computes it: month-by-month, lifetime-long, and skeptical of any rule of thumb that hasn't been run through the math.