Roth conversion calculator
Compare a planned Roth conversion with leaving pre-tax savings alone. The model follows retirement income, spending, federal tax, estimated state tax, Medicare IRMAA, required distributions, and account balances through the age you choose.
Advanced assumptions
Scenario comparison
Conversion schedule
Account phases, conversions, five-year periods, withdrawals, and Social Security by owner age.
Conversion five-year periods are informational only.
Best-tested strategy
Each cell tests one annual conversion amount from its start age through the final conversion age. The highlighted cell is the best tested result, not a guarantee of a global optimum.
After-tax advantage
Selected strategy after-tax wealth minus its no-conversion baseline. Above zero the strategy leads; below zero the baseline leads.
Taxable income and bracket room
Ordinary income, taxable Social Security, RMDs, additional withdrawals, and conversions for the active scenario, with the selected bracket ceiling where applicable.
Tax and Medicare costs
Annual federal tax, entered state-tax estimate, and income-related Medicare premiums under the strategy and no-conversion baseline.
Account mix by age
Pre-tax, Roth, and taxable balances for the active scenario in the selected display.
Annual projection
Income, spending, conversions, distributions, taxes, withdrawals, balances, after-tax wealth, and baseline differences are aligned across scenarios.
| Tax year | Scenario | Age | Income | Spending | Conversion | RMD | Federal tax | State estimate | IRMAA | Traditional withdrawal | Roth withdrawal | Taxable withdrawal | Traditional | Roth | Taxable | After-tax wealth | Vs. baseline |
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What this model assumes
- The selected policy is always measured against a matching no-conversion baseline. “Best tested” means best among the displayed start-age and annual-amount grid, not a personalized recommendation or a mathematical global optimum.
- Each year takes any required minimum distribution first, resolves spending-driven Traditional withdrawals and the selected conversion policy, calculates tax and Medicare IRMAA, finishes funding spending, and applies growth. An RMD is never converted.
- Spending is funded from current cash, taxable savings, additional pre-tax withdrawals, and Roth in that order. Accounts stop at zero; unmet spending makes a plan infeasible rather than creating a negative balance.
- Federal estimates start from 2026 law, inflate indexed thresholds in unpublished future years, and model taxable Social Security and the two-year IRMAA lookback. IRMAA charges only the Part B and/or Part D components selected for each enrolled person. Future law and actual Medicare premiums can differ.
- Pre-retirement wages and benefits affect tax but, because no pre-retirement spending or savings rate is entered, their unused cash is not added to the modeled accounts. Net RMD proceeds remain in taxable savings.
- State tax is an effective rate entered by you, not a state-by-state return. Remaining pre-tax money is valued after a modeled equal drawdown over the entered number of years.
- The model does not include IRA basis and Form 8606 pro-rata treatment, ACA subsidies, capital-gains basis, AMT, NIIT, tax credits, QCDs, early-withdrawal penalties, or separate Roth conversion five-year lots.
Calculations are estimates based on your assumptions and are for education, not financial, tax, legal, or investment advice. Actual results may differ. Read the financial disclaimer.