How the calculator computes each RMD
The calculator is a deterministic engine that maps each account to its statutory aggregation group, selects the correct life-expectancy table, and divides the prior-year-end balance by the resulting distribution period. No randomness, no estimation, no rounding beyond the cent.
Step 1 — Classify each account
Each account is mapped to one of nine statutory types: Trad IRA, Roth IRA, 401(k), 403(b), SEP IRA, SIMPLE IRA, QRP, Inherited IRA, Inherited Roth IRA. The user-supplied label ("Vanguard Trad IRA") is for display only — classification is by the dropdown selection.
Step 2 — Determine the aggregation group
- Trad / SEP / SIMPLE IRAs → one IRA pool per 26 CFR §1.408-8 Q-9
- 403(b) plans → one 403(b) pool per §1.403(b)-6(e)(7)
- Each 401(k), each QRP → its own group, separate per plan, per §1.401(a)(9)-8 A-1
- Inherited IRAs → one group per (decedent, account-type) tuple per §1.408-8 Q-9
- Roth IRAs (owner) → exempt; flagged as "no RMD required"
- Roth 401(k) post-2024 → exempt under SECURE 2.0 §325
Step 3 — Select the table
- Owner mode: Uniform Lifetime (Pub 590-B App. B). Joint Life (App. D) only when the user flags a sole-beneficiary spouse 10+ years younger.
- Beneficiary mode: Single Life (Pub 590-B App. C). EDB classification determines whether the divisor is recomputed each year (EDB stretch) or subject to the 10-year rule.
Step 4 — Compute and aggregate
for each account A: divisor = lookup(table, age, [spouse_age]) A.rmd = round(A.balance / divisor, 2) for each group G: G.total = sum(A.rmd for A in G) output.total = sum(G.total for G in groups)
Step 5 — Verification gate (operator-blocked before apex launch)
Per the IDEA-BRIEF activation gate, before the apex domain ships, the operator must hand-trace at least three IRS Pub 590-B Appendix B/C/D worked examples end-to-end and confirm the calculator reproduces each example to the cent. The current code path passes 23 unit tests covering the formula correctness, statutory grouping, divisor anchor values, EDB/exempt branches, and the §4974 excise-tax calculation. End-to-end IRS-example reproduction remains gated.
Privacy
All calculations run in the browser. Account balances, ages, and decedent labels never leave the device. No telemetry of input values is collected; analytics records only page views and anonymized country (consent-gated under default-DENIED Consent Mode v2).