Decumulation Studio
Joint Roth conversion and withdrawal-sequencing optimizer under bracket, IRMAA, ACA, LTCG, NIIT, RMD, and Roth 5-year-clock constraints.
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What it does
Decumulation Studio compares schedules for Roth conversions and withdrawals by account. Choose one goal. Fill a tax bracket or stay below an IRMAA tier. You can also maximize real ending wealth or lifetime ACA credits, or minimize lifetime tax present value. Compare the proposed schedule with a baseline that makes no conversions and uses simple withdrawal ordering.
Features
- Joint conversion and withdrawal schedule by year and account.
- Goals for tax brackets, IRMAA, ACA credits, lifetime tax, and real ending wealth.
- A yearly view of the limits that shaped each schedule.
- The modeled cost of an additional dollar of conversion or withdrawal by year.
- A breakdown of ordinary tax, NIIT, capital gains, ACA, IRMAA, and state tax for a selected year.
When to use it
- Compare withdrawal order and Roth conversions after retirement under the same household, return, and inflation assumptions.
- See which years approach a tax bracket, Medicare premium tier, or ACA subsidy threshold.
The planner is deterministic. It does not model random return paths or guarantee a global optimum.
Open the Decumulation StudioPro workflow
Pick a household, set the plan horizon and spending, choose an objective, and inspect the proposed schedule alongside a no-conversion baseline.
Main inputs
- Plan anchor: start year and horizon years. Every dated rule (RMD, IRMAA y-2 lookback, ACA regime) resolves from the start year.
- Household: the selected household supplies members, accounts, filing status, resident state, ACA inputs, and prior IRMAA MAGI history.
- Assumptions: nominal asset return, inflation rate, and real annual spending.
- Objective: bracket fill, IRMAA tier ceiling, lifetime ACA premium tax credit, lifetime tax present value, or real terminal wealth.
- Withdrawal policy: taxable-first, traditional-first, or Roth-last sequencing.
- Constraint caps: ordinary bracket cap, optional IRMAA tier ceiling, optional LTCG 0% preservation, and optional NIIT prevention.
How to interpret results
- Action schedule: conversion and withdrawal amounts by year and account.
- Binding-constraint rows: the cliff or cap that bound each year for the proposed schedule and the baseline.
- Marginal surface: dollar-by-dollar cost of additional conversion or withdrawal pressure across the horizon.
- Year drill: ordinary marginal, LTCG bump, NIIT delta, IRMAA delta (y+2), ACA delta, and state marginal for a chosen year.
Known scope
- Saved analyses for this tool are private-only. The share system does not register generic public share links for Decumulation Studio runs.
- ACA FPL modeling supports contiguous states/DC, Alaska, and Hawaii poverty-guideline tables.
- The optimizer is a bracket-fill heuristic plus a marginal-cost search. It is not a stochastic or globally optimal solver.
Cliff vocabulary
Glossary
- MAGI (Modified Adjusted Gross Income)
- AGI with certain items added back. Each cliff uses its own MAGI definition. NIIT, IRMAA, and ACA subsidies use different bases. Thus, one conversion can have a different distance from each cliff.
- IRMAA y-2 lookback
- Your MAGI from two years earlier sets the Medicare premium surcharges in a given year. A conversion this year raises premiums two years from now, which is why results show IRMAA deltas at y+2.
- ACA Premium Tax Credit (PTC)
- The subsidy that lowers marketplace health-insurance premiums, based on household income relative to the federal poverty level. Conversions raise income and can shrink or eliminate the credit.
- FPL (Federal Poverty Level)
- The income benchmark, scaled by household size, that ACA thresholds use as a base (for example 400% of FPL).
- SLCSP (Second-Lowest-Cost Silver Plan)
- The benchmark marketplace plan premium used to compute the ACA credit. The planners need its premium to value subsidy loss in dollars.
- Roth 5-year clock
- Each conversion starts a five-year waiting period before that amount can be withdrawn penalty-free (before age 59 1/2). The planners track a clock per conversion year.