The rules underneath every projection, made real.
Most retirement calculators plug your numbers into a rough rule of thumb. The TriSolaris Planner℠ runs an actual year-by-year tax-and-cash-flow engine built on the real 2026 federal tax brackets, the real IRS RMD and SEPP tables, the real ACA and Medicare IRMAA surcharge rules, and a genuine stochastic Monte Carlo simulation — not a static illustration. This page explains how, in plain language.
Four layers of analysis, run together.
Every plan gets a deterministic baseline, a stochastic simulation, a real historical replay, and a set of scripted stress scenarios — not just one number.
Deterministic Projection
A year-by-year cash-flow engine that sequences income, spending, taxes, and account withdrawals exactly the way a real retirement unfolds — one age at a time, compounding forward through your full planning horizon.
Monte Carlo Simulation
Thousands of possible futures, not one. Each trial draws its own correlated returns across five asset classes — a Cholesky-decomposed correlation matrix, not independent random numbers — and its own stochastic inflation path, then applies a dynamic Guyton-Klinger spending guardrail.
Stress Testing
Twelve named, scripted scenarios — from a 1973-style stagflation shock to a Lost Decade to two Japan-style decades of near-zero returns — each re-run as its own 750-trial mini Monte Carlo, reporting seven separate outcome metrics.
Historical Backtest
Replays your exact spending and withdrawal strategy against real historical market-return sequences — 1929, 1966, 2000, 2008 — rather than randomly generated ones, showing how the same plan would actually have fared starting in each real year, not just a simulated one.
Accounts are drawn down in the order you choose, not all at once.
When spending, taxes, and healthcare costs exceed your income in a given year, the engine funds the gap in whichever sequence you configure — not a one-size-fits-all default.
- Step 1Taxable, pretax, or Roth — your orderDrag-reorder which bucket is drawn down first, second, third. The default is taxable → pretax → Roth, but whatever order you choose applies identically across the deterministic projection, Monte Carlo, and Stress Test — not just the headline number.
- Step 2Roth conversions & RMDs come first within pretaxWherever pretax lands in your order, Roth conversions and Required Minimum Distributions are still resolved before any discretionary pretax withdrawal — the IRS doesn't let you reorder those.
- Step 3Asset-class order, and a downturn overrideWithin each account, choose which asset class liquidates first — cash, bonds, alternatives, international, US stocks — plus an optional separate policy for down-market years, so a bad year doesn't force you to sell equities at the bottom.
- Step 4Deferred comp & HSAThe stochastic engines (Monte Carlo and Stress Test) always keep these as final fallback tiers, even if you didn't explicitly order them that way — a retiree actually facing depletion would tap these too before running out.Fallback tier
Real brackets and real statutory thresholds.
Taxes aren't estimated with a flat rate — the engine applies the actual rules, bracket by bracket.
Real 2026 tax brackets
Real marginal federal brackets for both MFJ and single filers — including the single-filer table's real top-bracket threshold, which isn't simply half of the joint figure.
Tax Foundation, 2026 Tax Brackets and Federal Income Tax Rates
State & local income tax
Flat rates you configure for both your state and any local/city income tax, applied to taxable income each year.
Net Investment Income Tax
3.8% on the lesser of net investment income or the amount your MAGI exceeds a fixed $250,000 (joint) / $200,000 (single) threshold — never inflation-indexed since enactment.
IRC §1411
Capital gains on concentrated stock
Long-term capital gains tax on the embedded-gain portion of proceeds when a concentrated single-stock position is sold to fund spending.
AMT exposure flag
Flags when income crosses a documented exemption-phaseout estimate, so you know when a real AMT calculation is worth running.
The rules that only show up once you retire.
RMDs, early-withdrawal penalties, healthcare subsidies, and Medicare surcharges each have their own real statutory mechanics — modeled as such.
Required Minimum Distributions
Your RMD each year is your combined Traditional IRA and 401(k) balance divided by the real IRS divisor for your age — not an approximated percentage.
IRS Uniform Lifetime Table
72(t) / SEPP early withdrawals
All three IRS-approved distribution methods — RMD, amortization, and annuitization — computed against the real IRS life-expectancy divisor table, with the 5-year / age-59½ window enforced automatically.
Rev. Rul. 2002-62; 26 CFR §1.401(a)(9)-9, Table 1
ACA subsidy cliff
Models the real, current-law premium tax credit cliff — not the temporary pandemic-era enhancement that expired at the end of 2025 — so you see the subsidy cliff you'd actually face.
IRC §36B; 2024 HHS Federal Poverty Guidelines
Medicare Part B/D + IRMAA
The real 5-tier income-related monthly adjustment surcharge, driven by your actual MAGI from two years earlier — the real statutory lookback, not this year's income.
CMS, November 14, 2025 release (based on 2024 MAGI)
Estate tax
Federal exemption presets (current law vs. a modeled post-2025 sunset) plus flat top-rate approximations for the 13 states that levy their own estate tax, with proper Qualified Charitable Distribution handling.
SEPP schedule break
Models the real cost of breaking a 72(t) payment schedule early — the retroactive 10% penalty reapplied to every prior distribution, plus IRS underpayment interest, computed year by year rather than left as a vague warning.
IRC §72(t)(4)
Employer plan type
401(k) and 403(b) share the standard 10% early-withdrawal penalty and Rule-of-55 exception; a governmental 457(b) is exempt from that penalty entirely, at any age — a real, materially different rule the engine applies automatically based on your plan type.
26 USC §457(a)
Non-qualified annuities
Applies the real exclusion-ratio rule to annuity income — part of each payment is tax-free return of your original premium until it's fully recovered, the rest taxable as ordinary income.
IRC §72(b)
Two rules colliding in one real plan.
Both exhibits below are read straight off a sample plan shipped inside the Planner — Elena (52) & Jordan (51), Seattle WA — not rounded or staged for effect. Load that same plan and every number here reproduces exactly.
A Roth conversion that trips an IRMAA tier two years later
Elena and Jordan retire at 56 and 55, nine years before Medicare, and convert traditional balances to Roth throughout the gap — sized to a single $220,000 MAGI ceiling. That one input trips three separate rules the engine tracks independently.
| Age | MAGI | ACA subsidy | NIIT | Medicare / IRMAA |
|---|---|---|---|---|
| 56 (2030) | $394,192 | $0 of $19,000 premium | $839 | — |
| 60 (2034) | $394,192 | $0 of $23,095 premium | $1,212 | — |
| 63 (2037) | $220,000 | $0 of $26,735 premium | $0 | Clears the $218,000.01 MFJ Tier 1 IRMAA threshold by $2,000 |
| 65 (2039) | $220,000 | Medicare begins | — | Part B/D arrives pre-surcharged: $7,888/yr, Tier 1 — set by the age-63 MAGI, 2 years earlier |
At 63 their MAGI clears the 2026 MFJ Tier 1 IRMAA threshold ($218,000.01) by $2,000. Under the real 2-year CMS lookback — not this year's income — that figure is what sets their Medicare premium two years later, at 65: $7,888 that year, already in Tier 1, versus roughly $4,183 for a household of the same age with no surcharge. NIIT is $0 in these particular conversion years since MAGI stays under the $250,000 MFJ threshold — but it's very much live earlier in the same bridge (ages 56–60, $839–$1,212/year), when SEPP distributions and deferred-comp payouts push MAGI to $394,192 and the ACA subsidy is already fully gone.
IRC §1411; IRC §36B; CMS IRMAA release, November 14, 2025
The real cost of breaking a 72(t) schedule
Elena elects a 72(t)/SEPP plan at 56 — amortization method, $141,992 every year, running the mandatory 5-year window (56–60). Deviate from that exact amount even once, and every prior distribution is retroactively disqualified.
| Schedule breaks at | Years penalized | Distributions affected | 10% penalty | Total cost |
|---|---|---|---|---|
| 57 (one year in) | 1 | $141,992 | $14,199 | $15,335 |
| 61 (window's final year) | 5 | $709,958 | $70,996 | $89,965 |
"Total cost" is the retroactive 10% penalty (IRC §72(t)(1)) reapplied to every prior distribution, plus IRS underpayment interest accrued from each distribution's own year forward to the year the break is discovered — computed year by year, not left as a flat warning. No dedicated 72(t) calculator models the bust; most retirement planners don't model the penalty at all.
IRC §72(t)(4); Rev. Rul. 2002-62
Search for the best choice, not just run one plan.
Four dedicated optimizers search a real range of choices for each decision — every candidate is only accepted if it clears a Monte Carlo success-probability target, never judged on the single deterministic path alone. Beyond those, more tools compare specific decisions against your whole plan.
Optimize: earliest retirement age
Searches a window of retirement ages to find the earliest one whose Monte Carlo success probability actually clears a target — never just the deterministic base case.
Optimize: Social Security claiming age
Searches every legal claiming age to find the one whose Monte Carlo success probability clears your target while leaving the most money on the table.
Optimize: withdrawal order
Searches every possible priority order across taxable, pretax, and Roth to find the one whose Monte Carlo success probability clears your target while leaving the most money on the table.
Optimize: Roth conversion ceiling
Searches every finite federal tax-bracket ceiling for the taxable-income ceiling your plan fills headroom to each year, to find the one whose Monte Carlo success probability clears your target while leaving the most money on the table.
Deferred compensation elections
Compares lump-sum vs. 3/5/10-year payout elections against the marginal tax rate and IRMAA exposure each one creates the year it hits.
Sensitivity ("tornado") analysis
Perturbs investment return, inflation, spending, retirement age, Social Security claim age, and (when they apply to your plan) ACA premium growth and home appreciation, one at a time, to show which single assumption moves your outcome the most.
Asset allocation & rebalancing
Glide paths, annual and guardrail-triggered rebalancing, and configurable downturn-withdrawal policies — favor bonds, favor cash, or sell pro-rata — layered on top of the correlated simulation.
Cash flow visualization
A Sankey diagram traces every dollar for a chosen year — guaranteed income and withdrawals flowing in on the left, spending and taxes flowing out on the right — so where the money actually goes is visible at a glance.
What everything above is built on.
- IRS Uniform Lifetime Table (Required Minimum Distributions)
- IRS Single Life Expectancy Table, 26 CFR §1.401(a)(9)-9, Table 1 (72(t)/SEPP)
- Rev. Rul. 2002-62 (SEPP distribution methods)
- IRC §72(t)(4) (SEPP schedule modification penalty)
- IRC §72(b) (non-qualified annuity exclusion ratio)
- 26 USC §457(a) (governmental 457(b) early-withdrawal exemption)
- IRC §1411 (Net Investment Income Tax)
- IRC §36B and the 2024 HHS Federal Poverty Guidelines (ACA premium tax credit)
- CMS Medicare Part B/D IRMAA release, November 14, 2025 (based on 2024 MAGI)
- Tax Foundation, "2026 Tax Brackets and Federal Income Tax Rates"
Some figures above — the AMT exemption threshold, the ACA poverty-guideline table, the IRMAA tiers, and the estate-tax exemption presets — are documented estimates as of the date noted, not live feeds. Always verify current-year numbers against IRS and CMS guidance directly. Nothing on this page or in the TriSolaris Planner℠ is tax, legal, or investment advice.
See our Disclosures for the full picture.