How QuantCalc Models Retirement Taxes

Question 1

Does QuantCalc account for taxes in retirement projections?

Accepted Answer

Yes. QuantCalc's tax-aware mode models federal and 51-jurisdiction (50 states plus D.C.) income tax, Social Security taxation, Medicare IRMAA surcharges, long- and short-term capital gains, the Net Investment Income Tax, Required Minimum Distributions and Roth conversions, under 2026 law. The ACA premium-subsidy cliff is not part of the simulator's tax-aware mode; the separate ACA Bridge Planner and Roth Conversion Planner model it. Tax-aware mode is included in the free tier. With it switched off, the Monte Carlo simulation models no tax: each withdrawal is treated as money to spend, before any tax.

Question 2

Is tax paid out of the portfolio, or out of my spending figure?

Accepted Answer

Out of the portfolio. In Tax-Aware Mode your spending figure is what you spend after income tax. Each year the engine withdraws enough to fund that spending plus the year's federal and state tax, Medicare surcharges and any penalties, and pays the bill from the accounts it drew, so your success rate and ending balances depend on your state and withdrawal order. With Tax-Aware Mode off, taxes are not modelled and the spending figure is the total withdrawal.

Question 3

How does QuantCalc handle Social Security taxation?

Accepted Answer

Social Security is included in taxable income according to the provisional-income rules, under which up to 85% of benefits can become taxable as other income rises. This captures the Social Security 'tax torpedo,' where an extra dollar of withdrawals or conversions can pull more of your benefit into taxable income.

Question 4

How does QuantCalc model Medicare IRMAA surcharges?

Accepted Answer

IRMAA (the income-related Medicare Part B and Part D premium surcharge) is modeled as a set of income cliffs based on modified AGI, reflecting the two-year lookback. Because a single dollar over a threshold adds a full surcharge tier, IRMAA is included in the year-by-year withdrawal-optimization cost so plans can avoid tipping over a bracket.

Question 5

Does QuantCalc model state income tax, and how accurately?

Accepted Answer

It models all 51 jurisdictions (50 states and D.C.) with each state's statutory treatment of retirement income — pension exclusions, Social Security exemptions, and capital-gains rules. Income is source-typed, so a pension, an IRA withdrawal, and Social Security are each taxed by the state according to that state's specific law rather than lumped together.

Question 6

How are capital gains and the NIIT handled?

Accepted Answer

Long-term capital gains are taxed at the preferential 0%, 15%, or 20% rates, stacked on top of ordinary income (so the applicable rate depends on total income), and the 3.8% Net Investment Income Tax applies once modified AGI clears its threshold. Only the appreciated portion of a taxable-account withdrawal is taxed; the return of cost basis is tax-free. The model recognizes the 0% long-term-gains bracket, where low ordinary income can let a retiree realize gains at zero tax. A year whose sales net to a capital loss deducts up to $3,000 of it ($1,500 married filing separately) from other income and carries the rest forward, short-term and long-term separately (IRC 1211(b) and 1212(b)).

Question 7

How does QuantCalc evaluate Roth conversions?

Accepted Answer

The optimizer weighs converting traditional balances to Roth in low-income years — 'filling' a tax bracket — against the future taxes those conversions avoid (lower RMDs, less Social Security taxation, and reduced IRMAA exposure later). It prices the IRMAA surcharge a conversion can trigger, since a conversion that trips a tier can cost more than it saves. The ACA subsidy cliff is priced only by the separate Roth Conversion Planner (the ACA Bridge Planner), not by the simulator's tax-aware mode.

Question 8

How are Required Minimum Distributions (RMDs) modeled?

Accepted Answer

RMDs are enforced from the SECURE 2.0 start age — 73 for those born 1951–1959 and 75 for those born 1960 or later — taken from the birth year you give, or 2026 minus your age when you give none, so conversion and IRMAA timing line up with the correct first-RMD year. The plan always takes at least the RMD, so it never incurs the excise tax on a shortfall (25%, or 10% when corrected in time, under IRC section 4974); the federal tax API computes that tax for a shortfall you enter. By default the planner takes one RMD on the household's combined traditional balance at the primary owner's age. Give the spouse's share of the traditional balance (married filing jointly, with the spouse's age) and it figures each spouse's RMD separately, as IRS Publication 590-B does: each on their own balance from their own start age, with the Uniform Lifetime table, or the Joint and Last Survivor table when the other spouse is the sole beneficiary and more than 10 years younger, and with each spouse's QCDs from their own IRA; after the spouse's death the survivor treats the inherited IRA as their own. Employer plans are not figured separately from IRAs, the first RMD's April 1 required beginning date and the still-working exception are not modelled, and the primary owner's own death is not modelled: the plan follows the primary owner to the plan end.

Question 9

Does QuantCalc model the ACA subsidy cliff for early retirees?

Accepted Answer

Yes, in the ACA Bridge Planner (also inside the Roth Conversion Planner), not in the simulator's tax-aware mode. For retirees under 65 on ACA marketplace coverage, it models the premium tax credit and the 400%-of-federal-poverty-level subsidy cliff, which returned for 2026 as the enhanced (cliff-free) subsidies expired. A pre-Medicare bridge can be optimized to keep modified AGI under the cliff while still funding spending and, where beneficial, doing Roth conversions.

Question 10

How are the standard deduction and the 2026 senior deductions handled?

Accepted Answer

Ordinary income is computed after the standard deduction for the filing status, plus two age-based additions from the year a filer turns 65: the additional standard deduction for the aged under IRC §63(f) ($1,650 per qualifying married filer or $2,050 unmarried for 2026, granted per 65+ spouse on a joint return, with no income phase-out), and the OBBBA §70103 senior deduction ($6,000 per qualifying individual 65+, available for tax years 2025–2028, phasing out at 6% of modified AGI above $75,000 single / $150,000 joint, and unavailable to married-filing-separately filers).

Question 11

What is QuantCalc's approach to tax-efficient withdrawal sequencing?

Accepted Answer

Rather than a fixed rule like 'taxable first, then traditional, then Roth,' the engine simulates a set of whole-retirement withdrawal orders on the same market paths — fixed orders, bracket- and surcharge-tier fills from traditional, and bracket- and surcharge-tier fills paired with a Roth conversion for the room left over — costing each year's federal income tax, capital-gains tax, the NIIT, state tax, IRMAA and any early-withdrawal penalty, and recommends the order with the lowest present value of lifetime tax including tax still owed on any traditional balance left at the end. A single-year lowest-tax mix is not among them — it was removed from the search in September 2026 after losing to drawing traditional first on every realistic long plan tested, and survives only as a comparison in the published withdrawal-order study.

Question 12

Which filing statuses does QuantCalc support?

Accepted Answer

Single, married filing jointly, married filing separately and head of household, each with the federal brackets, standard deduction, senior deductions and IRMAA schedule for that status (head of household uses the single IRMAA schedule, as CMS does). Qualifying surviving spouse is available on the federal tax API, not in the retirement simulator, which files a widowed spouse as single from the year after the death.

Question 13

What tax items does QuantCalc deliberately not model?

Accepted Answer

The engine is built for retirement-income planning, and several tax items sit outside the planner's scope: net unrealized appreciation on employer stock, estate and inheritance tax, trust taxation, federal tax credits outside a year with wages or self-employment income (in such a year the planner figures the earned income credit without a child, the saver's credit for 2026 and the credit for the elderly; it has no dependents), itemized deductions (the simulator uses the standard deduction), the additional standard deduction for blindness, exceptions to the 10% early-withdrawal tax (such as leaving an employer at 55 or substantially equal periodic payments), the 25% and 28% capital-gains rates, and the ACA premium tax credit (the separate ACA Bridge Planner prices it). Two items the planner models only when the plan supplies them: per-owner RMDs (with the spouse's share of the traditional balance; otherwise one RMD on the combined balance at the primary owner's age) and local income taxes (with a chosen locality; otherwise only the Indiana and Maryland county taxes). The AI-assistant connector sends neither: its runs take one RMD on the combined balance at the primary owner's age and include only the Indiana and Maryland county taxes, at the state's average county rate. The planner prices wages and payroll tax, self-employment tax and the qualified business income deduction under IRC section 199A only through Wages and Self-employment life events: those years carry FICA or self-employment tax, the Additional Medicare Tax, the section 199A deduction and the Social Security earnings test with its recredit at full retirement age; without such an event the simulator has no wage input. Rental real estate income is priced the same way, only through Rental income life events: Schedule E with the passive-activity loss limit (Form 8582, the $25,000 allowance phased out between $100,000 and $150,000 of modified AGI) and its carryforward on each path. Inherited IRAs are priced through Inherited IRA life events: each year's distribution under the beneficiary's rule (the 10-year rule, a life-expectancy payout, the 5-year rule) is ordinary income with no 10% early-withdrawal tax. The alternative minimum tax (Form 6251) is figured in every year. The federal tax API, which prices a single year, also covers itemized deductions, blindness, the early-withdrawal exceptions, the foreign tax credit, the credit for the elderly or disabled, the saver's credit, the child tax credit, the earned income credit, rental real estate, inherited-account RMDs and the 25% and 28% rates. None of the items left out are approximated or quietly defaulted to zero-effect: they are absent, so a plan whose outcome turns on one of them needs work this engine does not do. The code records the same limits where they bite: the state module notes that Montana's section 199A carve-out is not modeled.

Question 14

Does QuantCalc model local or city income tax?

Accepted Answer

Yes, when the plan names a locality. Choose your city, county, school district or other taxing locality (the API takes its official code in localities) and the planner computes that locality's income tax with the state engine's own rules for it and adds it to the state tax each year. Each kind reaches its own base: Pennsylvania's local earned income tax reaches only earned income, so a retiree whose income is a pension owes $0 of it; Philadelphia's School Income Tax reaches unearned income such as dividends; New York City's tax is figured on the New York return; a Maryland county applies its own rate or brackets. In later years each local amount moves the way its law moves it: the law holds 13 of the 15 kinds fixed; Philadelphia's enacted rate schedule steps its wage, earnings, net profits and school income tax rates down to 3.70% from 2029; Portland Metro's thresholds follow the published figures ($132,000 / $211,000 for 2027) and are held at them after that, because the yearly inflation adjustment's index and rounding are not published; and Multnomah County's rates stay at their 2026 level, because the start year of its enacted 0.8% increase is not settled. Without a locality, Indiana county local income tax under IC 6-3.6 and the Maryland county and Baltimore City taxes are still applied, at the rate you enter or the state's population-weighted county average, and other states' local income taxes are not included.

Question 15

Does QuantCalc model state retirement-income exclusions and Social Security exemptions?

Accepted Answer

Yes, per state, as part of the 51-jurisdiction state module. Many states exempt qualified retirement income once the taxpayer passes a minimum age, and many exempt Social Security below an adjusted-gross-income threshold that differs between single and joint filers. Both are modeled state by state, so the state tax in a projection reflects the exclusions a client would actually receive rather than a flat rate applied to every dollar.

Question 16

Does the state tax use each spouse's own age?

Accepted Answer

Yes, when the plan gives the spouse's age. Many states test age per spouse on a joint return: a spouse who has reached the qualifying age claims the retirement exclusion, senior deduction or Social Security exemption against their own income, and the younger spouse's income stays taxable. The engine evaluates each such rule per spouse, applies the rules that are per return (one joint limit, or the older spouse's age) as per return, and without a spouse age keeps one household age for both. The methodology's state-tax section lists every per-spouse rule with its official source.

Question 17

How is military retirement pay taxed by state?

Accepted Answer

Military retirement pay is its own income type, separate from government and private pensions. Each state's 2026 rule is applied per retiree at the retiree's own age: full exemptions, dollar caps with age tiers, income tests, credits, and the states where military pay simply counts toward the general pension rules. Choose Military retirement pay as the pension type in the planner. The methodology has a 51-jurisdiction table with each state's official source.

Question 18

Are wages treated differently from other income in state tax?

Accepted Answer

Wages are ordinary income in every state, but a few states treat earned income specially and the engine models those: part of a retiree's earnings can count toward Georgia's retirement income exclusion, and Wisconsin and Ohio give joint filers credits that depend on each spouse's own earnings. Earned income tax credits and payroll levies are not modeled; local wage taxes are included only when the plan names a locality that levies one, such as a Pennsylvania local earned income tax or Philadelphia's wage tax. The methodology's state-tax section gives the rules and their sources.

Question 19

Is QuantCalc's output tax advice?

Accepted Answer

No. QuantCalc is a retirement-planning and education tool that models how taxes affect a plan under current law. It is not tax, legal, or investment advice. Tax law is complex and individual situations vary; consult a qualified tax professional or financial advisor before acting.

How QuantCalc Models Retirement Taxes

For financial advisors