RMDs

Required Minimum Distributions — the birth-cohort start ages, the IRS divisor, which accounts participate, and how a forced distribution interacts with the projection.

What is an RMD?

Once you reach a statutory age, the IRS requires you to withdraw a minimum amount from pre-tax retirement accounts each year, whether or not you need the cash. The withdrawal is taxable as ordinary income. Roth accounts are not subject to RMDs during the owner’s lifetime.

When RMDs begin

There is no single RMD age. SmartRetireCalc resolves the statutory “applicable age” from the account owner’s birth cohort (26 U.S.C. §401(a)(9)(C)(v), as amended by the SECURE Act of 2019 and SECURE 2.0 Act of 2022):

The primary account owner and a spouse are each resolved on their own birth cohort. When you have not supplied a date of birth, the engine falls back to age 73 (the current-law age for the 1951–1959 cohort now reaching RMD age). A user-entered RMD start-age override, when supplied, wins over the resolver.

How the annual RMD is calculated

In the projection this is applied at the start of each year (before that year’s growth, contributions, conversions, and spending), so the balance used is effectively the prior year-end pre-tax balance. The distribution is capped at the available pre-tax balance — the engine never forces a withdrawal larger than the account.

The Uniform Lifetime Table divisor

The divisor comes from the IRS 2022 Uniform Lifetime Table (Publication 590-B, updated for SECURE 2.0). The engine selects the row for the owner’s age in the distribution year. A few illustrative rows:

Example: a $500,000 pre-tax balance at age 75 → $500,000 ÷ 24.6 ≈ $20,325. The engine models the account owner only (Uniform Lifetime Table); it does not apply the Joint Life table for a much-younger spouse beneficiary.

Accounts subject to RMDs

RMDs apply to the pre-tax bucket — Traditional IRA, 401(k), 403(b), and similar employer plans modeled as pre-tax. Roth accounts are never subject to lifetime RMDs in the model, matching current law for Roth IRAs and (since SECURE 2.0) Roth 401(k)s. Savings, taxable brokerage, and the non-deductible Traditional IRA bucket are not driven by the RMD rule in the projection.

RMDs inside the projection

Each year, once the owner (or spouse) has reached their applicable age:

1. The RMD is computed and removed from the pre-tax bucket.
2. It is counted as ordinary income for the year’s federal tax and IRMAA MAGI (Taxes, Medicare & IRMAA).
3. It is applied to that year’s spending need first. If the RMD exceeds the planned spending, the surplus is modeled as reinvested into the taxable brokerage bucket (it left the tax-deferred account and was taxed).
4. If the planned withdrawal already exceeds the RMD, no additional forced withdrawal is needed.

See Projection Engine for the full annual order of operations.

RMDs and Roth conversions

The required distribution is satisfied first: in each projection year the RMD is forced out of the pre-tax bucket before the Roth-conversion amount is chosen, and the RMD is part of the ordinary income the Fill-to-Bracket and Fill-to-IRMAA solvers must fit under their ceilings. A conversion cannot be used to avoid an RMD — converted dollars and the RMD both count as ordinary income in the same year. This is why conversions are most useful in the years before RMDs begin. See Roth Conversions.

Limitations

• Uniform Lifetime Table only — no Joint Life & Last Survivor table for a more-than-10-years-younger sole-beneficiary spouse.
• RMD ages are whole years; the model does not track the half-year birthday or the first-year “delay to April 1 of the following year” election.
• Qualified Charitable Distributions (QCDs), still-working exceptions, and inherited-IRA RMD rules are not modeled here.
• The divisor table is the 2022 issuance; a future IRS update would need a table change.

Official sources

• 26 U.S.C. §401(a)(9)(C)(v) — the statutory 'applicable age'
• SECURE Act of 2019 §114; SECURE 2.0 Act of 2022 §107 — the birth-cohort age schedule (72 / 73 / 75)
• IRS Publication 590-B — Uniform Lifetime Table divisors (2022 issuance, updated for SECURE 2.0)