Roth Conversion Calculator

Estimates lifetime federal tax savings from a multi-year Roth conversion plan vs. no conversion. Uses simplified marginal-rate analysis — a specialist runs the full model (bracket filling, IRMAA, state tax, SS stacking).

What this calculator doesn't model (but the specialist does)

• Bracket filling precision. Converting into the top of the 22% bracket without spilling to 24% requires annual re-calibration against projected other income.
• IRMAA tier impact. Conversions that cross Medicare income thresholds trigger $1,600-$10,000/yr of extra premium costs.
• State tax variation. 9 states have no income tax (Roth conversions skip state tax too); high-tax states (CA, NY) penalize conversions more heavily.
• Social Security stacking. Once SS begins, up to 85% becomes taxable. Conversion income stacks on top.
• 5-year rule. Funds from each conversion locked for 5 years before penalty-free withdrawal.
• Pro-rata rule. Presence of after-tax IRA basis complicates the conversion math.
• Beneficiary planning. Roth inherited by heirs is tax-free; traditional inherited is taxable over 10 years.