Roth conversion: Can an adviser really cut taxes by 35%?

A claim that a Roth conversion will deliver a flat "35% tax saving" is usually a red flag rather than a reliable promise. A Roth conversion moves pre‑tax retirement assets (for example, a traditional IRA or 401(k)) into a Roth account; the converted amount is reported as ordinary income in the year of conversion and is therefore taxable. Broad percentage claims rarely survive a detailed tax modelling.

In practice, how much of a conversion is taxable depends on the composition of the account and IRS reporting rules. If you have after‑tax basis in traditional IRAs, the taxable portion may be reduced, but the IRS pro‑rata rule prevents cherry‑picking only the after‑tax dollars when multiple IRA balances exist. Filers must often use Form 8606 to report nondeductible contributions and conversions; failing to report basis correctly can lead to unexpected tax bills.

From a planning perspective, large conversions can push taxpayers into higher marginal brackets, increase Medicare IRMAA surcharges and interact with state income taxes—each of which can materially reduce or even eliminate the advertised "savings." Advisors should model not only the immediate federal income‑tax cost but also secondary impacts such as increased Medicare premiums and the loss of certain deductions and credits.

More broadly, Roth conversions are a tool for tax diversification and are most effective when the taxpayer reasonably expects future tax rates (or the tax exposure of heirs) to be higher than current rates. Legislative changes and individual circumstances (timing of Required Minimum Distributions, expected retirement income, state residency) can change the calculus, so a one‑size‑fits‑all percentage claim is inappropriate. Scenario analysis over multiple years gives a clearer picture of net benefit.

Most tax professionals recommend obtaining a written conversion model from the adviser, considering staged conversions to manage bracket effects, and paying conversion taxes from outside retirement accounts when feasible so the full converted balance stays invested. In short, demand numbers and run scenarios; only a detailed, personalized analysis can tell whether a conversion will reduce lifetime taxes — a blanket "35%" claim should be treated with skepticism.