Methodology & validation

Retirement tools notoriously disagree — the same plan can score 60% in one tool and 90% in another, and most tools won't show you why. RetireGolden's answer is to show its work.

One auditable ledger

Every result — the success rate, the Roth-conversion recommendation, the "how much can I spend" answer — comes from a single year-by-year ledger you can open and read. There is no separate "estimate" engine: the Monte Carlo simulation, the optimizer, and the reports all price against the same exact projection. If two numbers in RetireGolden ever disagree, that's a bug, not a methodology difference.

Checked against independent implementations

RetireGolden's calculations are tested against third-party references, none of which share code with it:

• Federal & state taxes — golden test cases are cross-checked against independent open-source tax engines maintained by policy-research communities.
• Roth-conversion optimization — a parity harness runs the same households through an independent open-source conversion optimizer and prices both tools' schedules on RetireGolden's own ledger, re-verified against pinned releases on a maintenance cadence.
• Social Security — claiming math is validated against the SSA's published rules (bend points, family maximums, survivor-benefit limits) and cross-referenced with widely trusted open-source claiming calculators.

Asset-location invariance, proven

A known six-figure bug class in Roth-conversion tools: quietly assuming Roth dollars are invested more aggressively than traditional dollars, so "conversion benefit" is really a hidden allocation change. RetireGolden holds portfolio-wide asset allocation constant across account types, and a dedicated fixture suite proves it: a tax-free conversion between identically-allocated accounts leaves every year's totals identical to the dollar, the entire estate benefit of a conversion is the tax term, and conversion candidates in the decision engine can never carry a hidden account or allocation change. If you choose different allocations per account, the engine prices that too — visibly, as your explicit setting.

Every parameter cites its source

Tax brackets, IRMAA tiers, ACA percentages, RMD tables, and Social Security parameters live in versioned data files with provenance — each value traceable to the Revenue Procedure, statute, or agency publication it came from, and refreshed annually on a documented schedule. The app shows the sources and vintages it is using in its disclaimer and provenance panel.

What RetireGolden deliberately simplifies

Honest scope beats false precision. RetireGolden is planning-grade, not filing-grade:

• AMT is modeled as a planning screen, not to filing precision; per-lot basis and every credit phase-out are simplified by design.
• The optimizer's in-solve model uses documented simplifications (for example, a single long-term-gains rate inside the solve); recommendations are then re-priced and validated on the exact ledger before you see them.
• Future-year tax parameters beyond published law are stand-ins, clearly marked.
• Nothing here is financial, tax, or legal advice — it's an educational model of current law. For the year you execute a major decision, verify with a professional.

Why it's free (and what that means for your data)

No accounts, no server, no data collection — your plan never leaves your device. There is nothing to sell because nothing is collected. See Sustainability & your data for what happens if the project ever winds down (short version: your data is a portable file you already have).