How it works
A Roth conversion ladder is the early-retiree tactic of moving traditional money into Roth deliberately, one tax bracket at a time, during low-income years. The mechanics are simple subtraction: your other taxable income plus the standard deduction leaves headroom below whichever bracket ceiling you target, and that headroom is the year's ideal conversion size. Convert more and the overflow is taxed at higher marginal rates — the mistake the ladder exists to prevent. Each converted amount also starts its own five-tax-year clock before it can be withdrawn penalty-free before age 59½, which is how year-one conversions become spendable in year six and bridge the gap to penalty-free access. This calculator sizes the annual fill, estimates the tax at your assumed marginal rate, and lays out the whole multi-year schedule until the traditional balance empties or the window closes. Bracket tops, deduction amounts and surtaxes like ACA premium subsidies or IRMAA move constantly, so treat every default here as an illustrative placeholder and re-run the plan each December.
Formula
Headroom = bracket top − max(0, other income − deduction) | Conversion = min(headroom, balance ÷ years) | Est. tax = conversion × marginal rate
Tips
- Pay the tax from outside funds so the full converted amount compounds tax-free.
- Stop filling when ACA subsidies, IRMAA surcharges or state cliffs would eat the savings.
- Each conversion seasons five tax years before penalty-free early withdrawal — stagger them.
- Re-run the plan every December against current bracket tables, not old defaults.
- Leave enough traditional money to fill low brackets later in retirement.
Frequently asked questions
- How much can I convert without jumping tax brackets?
- Subtract your other taxable income and deduction from the bracket ceiling you are filling. With $40,000 of other income, a $30,000 deduction and a $100,000 target top, headroom is about $90,000 — convert up to that line before every extra dollar costs the next rate up.
- How long does a Roth conversion ladder take to build?
- Most early retirees spread conversions over five to ten low-income years between leaving work and Required Minimum Distributions. A $120,000 balance cleared through five years of bracket-sized fills converts roughly $24,000 annually, though larger headroom lets bigger years finish sooner.
- What is the five-year rule on Roth conversions?
- Every conversion carries its own five-tax-year seasoning clock before its principal can come out penalty-free before 59½. Money converted in 2026 becomes accessible in 2031 — which is exactly why ladders start the year you retire rather than the year you need cash.
- Do Roth conversions affect Social Security taxes or Medicare premiums?
- They can. Conversion income raises provisional income, potentially taxing up to 85% of benefits, and big conversions two years ahead can cross IRMAA surcharge tiers (illustratively starting near $106,000 single). Front-load conversions in your fifties and taper before claiming begins.
- Should I convert everything to Roth at once?
- Rarely. A single giant conversion stacks every dollar at your top marginal rate, while spreading fills captures low-bracket years — often 12% instead of 22%+. Converting everything also hands over all the tax immediately instead of letting the government's share keep working.