Tax Conversion Planner

Finds the year-by-year Traditional → Roth IRA conversion schedule that maximizes your after-tax wealth, weighing brackets, the Social Security tax torpedo, Medicare IRMAA, ACA subsidies, RMDs and what your heirs will owe. Everything runs in your browser. Nothing is sent or stored.

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Load the settings saved in an Excel report from this planner, including any values you changed on its Inputs sheet. You can also drop the file here. It is read in your browser and never uploaded.

About you

Plan starts in tax year 2026. Required minimum distributions begin at age 75 for your birth year.

Birth yearCurrent ageFiling statusState income tax rate%Effective rate on income other than Social Security. 0% for states with no income tax.

Accounts today

Traditional IRA balance$After-tax basis in Traditional IRAs$Form 8606 basis. Makes part of each distribution/conversion tax-free (pro-rata rule). Usually $0.Roth IRA balance$Outside (taxable) account balance$Cash / brokerage funds available to pay taxes (and living expenses, if modeled).Outside account return (nominal)%Usually lower than the long-term market return used for the IRAs (e.g. cash or bonds). Tax drag is subtracted from it.

How will conversion taxes be paid?I can pay conversion taxes from other savingsAssumes you have enough outside funds. The tax is not taken out of the IRA. If the outside balance runs out it goes negative (extra funds needed), including for living expenses.Pay from my outside account balance, then from the IRAUses the outside balance above; once it runs out, tax is withheld from the converted amount. With living expenses on, spending is then drawn from the Traditional IRA (taxable), then the Roth.I cannot pay from outside fundsConversion tax is withheld from the IRA. Before age 59½ the withheld amount also incurs the 10% early-withdrawal penalty. The outside account is used only for living expenses.

Work & Social Security

Current annual wages$Today's dollars. Enter 0 if you are already retired.Retirement ageWages stop at this age.Social Security (household, per year)$Today's dollars at your claiming age; adjusted for inflation.Social Security start ageConversions make more of your benefit taxable (the “tax torpedo”); the model accounts for it.

Timeline

Start converting at ageLast conversion ageConversions above your RMD are allowed until this age.Estimated lifespan (evaluate wealth at age)The plan maximizes after-tax wealth at the end of this age, including the tax your heirs will owe.

Investment assumptions

Assumed investment return (nominal)%Traditional and Roth IRAs. The outside account has its own return (Accounts today).Inflation%Also indexes tax brackets, deductions, IRMAA tiers, and inflation-adjusted income.Tax drag on outside account%Annual return lost to taxes on the outside account.

Living expenses

Off: your other income is assumed to cover your living costs and its own taxes, so the outside account only receives RMDs and pays the extra tax on IRA money. That is why it can keep growing.

Model my living expenses

Future tax rates (what if)

Test a tax increase: ordinary income tax rates go up from a chosen year on income above a level you set. Applies to you and to your heirs.

Model a future tax-rate increase

Health insurance

Medicare IRMAA is always modeled from age 65 (based on income two years earlier).

I buy ACA marketplace insurance before Medicare (premium tax credit)MAGI last year (optional)$For the Medicare 2-year look-back. Blank = estimate.MAGI two years ago (optional)$

Heirs

Any Traditional IRA left at the end of your lifespan must be emptied by heirs within 10 years, taxed at their rates. Roth balances pass tax-free.

Number of heirsEach heir's other taxable income / year$Today's dollars; heirs are modeled as single filers.Heirs' state tax rate%

Other income

Pensions, rental income, interest, dividends, gains, etc. that affect your bracket. Social Security and wages are entered above. Tick QBI (§199A) for ordinary income that is qualified business income (for example some retired-partner payments): it earns a deduction of 20% of that income, phased out as taxable income rises from $201,750 to $276,750 (2026, single).

No other income added.