RMD Aggregation: IRAs Together, 403(b)s Together, Each 401(k) on Its Own

Can I take all my RMDs from one account?

Only within a kind. You compute the RMD of every account separately; then the IRS lets you add up your IRA RMDs and take the total “from one or more of the IRAs”, and likewise “take the total amount from one or more of the 403(b) contracts”, but “RMDs required from other types of retirement plans, such as 401(k) and 457(b) plans, must be taken separately from each of those plan accounts” (IRS RMD FAQs). An IRA withdrawal never satisfies a 403(b) or 401(k) RMD, or the other way round. Example at 75, divisor 24.6: two IRAs owe $18,293 together, which may come out of either; two 403(b)s owe $8,130, likewise; the two 401(k)s owe $8,130 and $3,659, each from its own plan. In all, $38,211.

The worked example: age 75 in 2026, balances on December 31, 2025, Uniform Lifetime Table (divisor 24.6); each RMD computed by the tax engine.
Key number	2026
IRA #1 ($300,000): counts toward the IRA total	$12,195
IRA #2 ($150,000): counts toward the IRA total	$6,098
403(b) #1 ($120,000): counts toward the 403(b) total	$4,878
403(b) #2 ($80,000): counts toward the 403(b) total	$3,252
401(k) #1 ($200,000): from this plan	$8,130
401(k) #2 ($90,000): from this plan	$3,659
IRA total: take from IRA #1, IRA #2 or both (IRS)	$18,293
403(b) total: take from 403(b) #1, #2 or both (IRS)	$8,130
All RMDs for 2026	$38,211

An estimate from QuantCalc’s open tax engine (federal 2.4.0, state 1.16.4) for the 2026 tax year. Not tax advice: your return depends on facts this page does not ask about, so check a move with your tax preparer or custodian before acting. RMD amounts only; the tax on them depends on your other income: RMD calculator. How the engine computes each line, with its official source: federal, state.

Your accounts: what comes out of where

Your age in 2026

IRA #1 balance on 12/31/2025 ($)

IRA #2 balance on 12/31/2025 ($)

403(b) #1 balance on 12/31/2025 ($)

403(b) #2 balance on 12/31/2025 ($)

401(k) #1 balance on 12/31/2025 ($)

401(k) #2 balance on 12/31/2025 ($)

Uniform Lifetime Table divisors from rmd.js. Leave a balance at 0 for an account you do not have. Roth 401(k), Roth 403(b) and Roth IRA balances owe no RMD while you are alive; leave them out.

The aggregation rules by account

Computed per account; withdrawn as below (IRS RMD FAQs; IRAs: 26 CFR 1.408-8)
Account	Where the RMD may come from
Traditional, SEP, SIMPLE IRAs	Total of all your IRA RMDs, from any one or more IRAs
403(b) contracts	Total of all your 403(b) RMDs, from any one or more 403(b)s
401(k), 457(b), other plans	Each plan pays out its own RMD
Inherited IRAs	Only with other IRAs inherited from the same person; never with your own

The still-working exception is per plan

If you still work for the employer that sponsors a 401(k) or 403(b), that plan’s RMDs may wait until the year you retire, unless you own more than 5% of the business; the exception never covers IRAs or the plans of former employers (IRS RMD FAQs).

Old 403(b) money

A 403(b) balance from before 1987 that the plan has tracked separately is not due until December 31 of the year you turn 75 (IRS RMD FAQs).

Fewer accounts, fewer RMDs to track

Rolling old 401(k)s into an IRA lets their RMDs join the IRA total. Converting part of the pre-tax balance to a Roth IRA before RMDs start shrinks every future RMD, because the RMD is computed on the traditional balance only: Roth Conversion Planner. Rules overall: RMD rules 2026; a missed plan RMD: RMD penalty calculator; the factors: RMD table 2026.

Paid tool An RMD is a fraction of the traditional balance on December 31, so every dollar you move to a Roth before then is a dollar no future RMD is computed on: a Roth IRA has no RMD while you are alive (IRS RMD FAQs). The Roth Conversion Planner works out how much to convert in each year from now to your plan end age to shrink those future RMDs: the federal and state tax each conversion costs, the IRMAA tier that year’s MAGI sets two years later, and the ACA subsidy it affects — beside the same years with no conversions, and downloadable as a PDF you keep. A planning tool, not advice: the numbers move when your assumptions do. Build my conversion schedule — Personal PRO ($49) → Roth Conversion Planner: see what is included, and price this year free, first →

An RMD is ordinary income on top of everything else you have that year. QuantCalc runs your whole retirement — withdrawals, RMDs, taxes, Medicare surcharges — year by year.

Run the free tax-aware simulation →

Common questions

Can I take my 401(k) RMD from my IRA?

No. Each 401(k) and 457(b) must pay out its own RMD; only IRAs may cover each other, and 403(b)s each other (IRS RMD FAQs).

Can I combine RMDs from multiple IRAs?

Yes: compute each IRA’s RMD, add them, and take the total from any one or more IRAs (IRS RMD FAQs). In the example, $300,000 and $150,000 at 75 owe $18,293 together.

Can 403(b) RMDs be aggregated?

Yes, among 403(b) contracts only: in the example $8,130 may come from either 403(b) (IRS RMD FAQs).

Do I need an RMD from my 401(k) if I still work?

Not from the current employer’s plan until the year you retire, unless you own more than 5% of the company; IRAs and former employers’ plans still owe RMDs (IRS RMD FAQs; Publication 590-B).

Sources

RMD rules 2026 → RMD calculator 2026 → 401(k) withdrawal calculator → RMD table 2026 → RMD penalty calculator → RMD age calculator →