Roth Conversion & Drawdown Optimizer
A free tool that plans your whole retirement cash flow: it funds your living expenses, pays the tax on your income and conversions from the right account, and finds the conversion schedule that leaves you the most after-tax wealth.
Result
What this plan is doing
Year-by-year plan
| Age | IRA | Roth | Taxable | RMD | Convert | Extra IRA draw | Roth draw | Taxable sold | Spending | Taxable inc | MAGI | Top rate | Medicare | Tax |
|---|
Reading the tax columns: Tax is the whole income-tax bill for the year — federal, state, the 3.8% investment surtax and any early-withdrawal penalty, all in one number. Medicare is separate and additional: it is a premium surcharge, not a tax, so it is never inside the Tax column. Add the two to get the cash the plan hands over that year.
Not tax or investment advice. This tool models your living expenses and draws them — plus the tax on your income and conversions — from your accounts in order (taxable → traditional → Roth by default), and picks the conversion schedule that maximizes after-tax wealth at the end. It still simplifies real tax law: a single real return; Social Security taxed at a flat fraction; long-term gains taxed at a flat rate (no 0%-bracket harvesting yet); and state income tax either as one flat rate you enter or, under Advanced assumptions, your state's real brackets — even then it ignores local and city income taxes, age-based deductions, and state-specific capital-gains rules, and the prefilled brackets are a starting point to check, not tax advice. IRMAA and NIIT can be modeled (2026 figures, off by default — see Advanced assumptions); dividend tax-drag and ACA-subsidy effects are not. Pre-59½ withdrawals from the IRA/Roth incur the 10% penalty; conversions never do. Results depend entirely on your assumptions. Confirm any plan with a qualified tax professional before acting. Built by Kind-of-Lost.
How this works
A Roth conversion means paying income tax now on money in a traditional IRA or 401(k) so it can grow tax-free in a Roth account for the rest of your life. But conversions don't happen in a vacuum — they compete with your living expenses, your capital gains, and which account pays the tax bill, for space in your yearly income.
This calculator treats the whole picture as one optimization problem instead of solving conversions in isolation. It's a linear program — built with Python, PuLP, and the CBC solver — that plans your full retirement cash flow at once: it funds your living expenses every year, decides which account pays for that spending and for the tax on your conversions and withdrawals, and finds the conversion schedule that leaves you with the most money after tax at the end of the horizon, not just the lowest conversion-tax bill.
It also handles pieces most free calculators skip: capital gains on your brokerage account, split into long-term and short-term and taxed at their own rates; an optional withdrawal order the optimizer can choose instead of a fixed taxable-then-traditional- then-Roth sequence; and a "spend it down" mode that finds the most you can spend every year while draining every account to roughly zero by the end.
It's built for people within a few years of retirement or already retired, with meaningful balances across traditional, Roth, and taxable accounts, who want an answer built on real optimization math rather than a spreadsheet rule of thumb. It's not a substitute for a CPA or financial planner — local income taxes and ACA subsidies aren't included — but IRMAA and NIIT are there under Advanced, and it's a real, free starting point. For the reasoning behind the model, see when a Roth conversion makes sense and the linear-program math behind this calculator.
Frequently asked questions
How is this different from a simple Roth conversion calculator?
Most Roth conversion calculators only decide the yearly conversion amount and assume your other accounts just grow untouched. This tool plans your whole retirement cash flow at once: living expenses, withdrawal order, and capital gains on your brokerage account. It finds the conversion schedule that produces the most money in your pocket after tax, not just the lowest conversion-tax bill in isolation.
What does "maximize after-tax wealth" mean, exactly?
It compares every plan by what's left across your traditional IRA, Roth IRA, and taxable brokerage at the end of your horizon, after subtracting the tax you'd still owe on the traditional balance and the embedded capital gain in the brokerage account. That number is your after-tax wealth, and it's what the optimizer maximizes.
What is the "spend it down" mode?
Instead of you specifying a living-expense number, this mode asks the solver for the highest constant amount you can spend every year, in today's dollars, while still funding taxes and RMDs, such that all three accounts land at roughly zero by your planning end age. It's a die-with-zero style plan rather than a wealth-maximizing one.
Does it really model my state taxes?
Two ways. By default it applies one flat rate you type in — a rough estimate, and the right answer for the nine states with no income tax. Under Advanced assumptions you can pick your state instead and get its real graduated brackets and standard deduction, prefilled and fully editable, plus switches for whether your state taxes Social Security and how much retirement income it excludes. Those last two are deliberately left to you: state retirement rules are where the answer actually turns, we don't ship them, and guessing them for you would be worse than asking.
What it still doesn't do: county or city income taxes (ten states have them, and Maryland's are large), age-based deductions, or state-specific capital-gains treatment. And the prefilled brackets are a convenience to check against your state's own tables — not tax advice.
What isn't included in this calculator?
It can model IRMAA (the Medicare Part B/D income surcharge, on the real two-year lookback, as the cliff it actually is) and the 3.8% Net Investment Income Tax — both on 2026 figures, both switched on under Advanced assumptions rather than by default, so the ordinary run stays instant. If a plan would have tripped either one, the notes under the result say so. Not modeled: ACA subsidy phase-outs, 0%-bracket capital-gains harvesting, and dividend or interest tax-drag on the brokerage. It uses a single real rate of return for every account, a flat long-term capital-gains rate, and one flat state rate rather than real state brackets. Treat the output as a starting point to bring to a CPA or financial planner, not a final plan.