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Methodology · chapter 1

Read your forecast with confidence.

Understand what the charts show, how your balances change each year, and which controls change your results. A worked example brings the numbers together.

Current model 2026 federal rules · 2025 state and localReading time 9-minute read
One ledger, two scalesAnnual cash flow + cumulative net worth
Example cash-flow graphFive annual bars show income above a zero line and taxes, housing, spending, and investing below it. A rising line shows cumulative net worth on a separate right-hand scale.$ in$0$ outworthY1Y2Y3Y4Y5

Illustrative shape—not a forecast or market prediction.

Reading the output

Three views of the same projection

Switching graphs does not run a second model. Each view reads the same settled year rows and emphasizes a different question.

01 · Movement

Cash flow

Above zero, the chart shows income, cash interest, gross account withdrawals, and property-sale proceeds. Below zero, it shows federal, state, local, payroll, sale, and withdrawal tax; housing; spending; debt payments; Medicare; contributions; and leftover cash swept into an account.

The line uses a separate right-hand scale and shows cumulative net worth.
02 · Location

Net worth

Each bar stacks where wealth sits at year-end: saved cash, home equity, pre-tax accounts, Roth accounts, brokerage, and interest- bearing cash accounts. A marker under the year means an account distributed money or a property was forced to sell; it does not necessarily mean the year had a gap.

The stack is gross assets; headline net worth also subtracts standalone debt. A hatched cap marks cash that remains unfunded after every allowed source is exhausted.
03 · Exit value

Taxable net worth

This is a hypothetical liquidation view: what the year holds, the estimated tax if taxable assets were sold or withdrawn together, and what would remain. It is an exit-value lens, not a prediction that the plan will liquidate.

Cash and principal are not taxed again; embedded gains and pre-tax balances are.
Headline net worthsaved cash + home equity + every investment account − standalone debt balances
Home equityprojected property value − remaining mortgage

Value follows the property’s change path. Debt follows annual amortization and is set to zero after a modeled sale.

Calculation order

One year closes before the next opens

The unit of time is a plan year. Month settings prorate income, spending, and events within that year; balances and tax are then settled annually. The closing state becomes the next year’s opening state.

  1. 01
    Advance property

    Update value, mortgage interest and principal, ownership costs, rent, the year's depreciation on a rental's building, purchases, and scheduled sales. Property tax is charged on a taxable value that follows the state's rule: capped growth from today's bill where a state caps assessments (California's Proposition 13, Florida's Save Our Homes, and their cousins — repriced when a modeled purchase lands), and the market value everywhere else.

  2. 02
    Build income and pre-tax saving

    Apply each stream’s active months and change curve; take any mandatory defined-benefit pension contribution off the pay; calculate payroll tax on the whole wage; fit pre-tax elections to compensation, MAGI rules, shared legal pools, and contribution limits.

  3. 03
    Price tax, finish saving, and grow accounts

    Add taxable interest and dividends; calculate federal, state and local income tax; fit after-tax saving to take-home pay; and record opening deposits and the employer match, stopped at whichever ceiling comes first — the plan document’s own or the year’s total-additions room. The year’s return applies to each opening balance in full, and to the money that arrives during the year for half of it — contributions, withdrawals and sweeps are all dated mid-year.

  4. 04
    Pay the year

    Add life-event costs, spending, standalone debt minimums, sale tax, Medicare, and IRMAA. This produces the year’s preliminary surplus or gap.

  5. 05
    Fund and close

    Process required minimum distributions (RMDs) first, then any strategy Roth conversion and inherited, user-scheduled, or Rule 72(t) substantially equal periodic payments. Fund named-account purchases and mandatory priorities, then cover a gap using the saved account-and-property selling order or allocate a surplus. Record the settled balances.

Roll-forward formulas

Flows move balances; returns revalue them

The chart never infers balances from the shape of a bar. Each account has a standing balance and, where relevant, a cost basis. Contributions, withdrawals, conversions, and growth are recorded separately before the closing balance is published.

Account balance before end-of-year fundingmax(0, opening balance × (1 + annual return) + (contributions + match) × √(1 + annual return) + opening deposit)

Contributions, withdrawals, required distributions and sweeps are dated mid-year, so each earns half a year of the return; the closing balance is what the next year’s return acts on.

Closing saved cashopening saved cash + every settled cash inflow − every settled cash outflow

Settled inflows include income, interest, sale proceeds, and distributions; outflows include tax, purchases, bills, debt, contributions, and surplus allocations.

After-tax liquidation valuenet worth − tax on modeled withdrawals and realized gains

What counts as growth

For an account, its configured flat or custom return—or the chosen historical calendar-year return—changes the standing balance. Dividend yield is handled separately so a brokerage dividend can be taxed and reinvested with its basis recorded.

What “shortfall” means

A shortfall is not merely a negative cash-flow year. The funding waterfall first tries required and scheduled distributions, available accounts, and any permitted property sale. Only the amount still uncovered is marked as a shortfall.

Controls above the graph

Display and simulation controls

ControlWhat changesDoes the plan rerun?
Today’s money

Discounts every finished year-row by the plan’s inflation rate.

No recalculation
Log scale

Bends only the chart geometry so large sale years do not flatten ordinary years.

No recalculation
CSV

Writes the readable years of the chart on screen to a spreadsheet file, band by band, in the money the chart is showing.

No recalculation
Cash flow / net worth / taxable

Reads a different set of fields from the same settled rows.

No recalculation
Real market

Uses an actual historical sequence wherever the selected series has coverage, then falls back to each account’s configured plan-year return.

Recalculates
Any plan input

Changes the assumptions supplied to the annual engine.

Recalculates
Today’s-money factor for plan year y1 ÷ (1 + plan inflation)⁽ʸ ⁻ ¹⁾

Tax is calculated first in that year’s dollars. Discounting the finished output never moves income into another bracket.

Illustrative ledger

How a single year becomes a closing balance

This deliberately simple example shows the reading order. It is not a tax example and does not represent a saved plan.

Money available

Wages & benefits$110,000

Rental income$12,000

Cash interest$1,000

Total in$123,000

Planned outflows

All modeled taxes$28,000

Housing, debt & spending$70,000

Planned investing$15,000

Total out$113,000

Settlement$10,000 left

Held as saved cash or swept into the selected account, depending on the plan’s cash-buffer setting.

Net-worth change is not necessarily $10,000: account returns, home appreciation, mortgage principal, standalone debt paydown, and changes in existing asset values also move the closing balance.

Interpretation boundary

Projection limits

It is conditional.

Every result follows the ages, dates, amounts, return paths, inflation, and rules currently in the plan.

It is annual.

Month choices prorate flows, but intra-year market timing, daily balances, and monthly budgeting are outside the model.

It is internally connected.

The plan pages, charts, annual details, tax analytics, reports, and strategy reruns read the same annual engine.

It is not a promise.

Flat returns are assumptions and historical returns are examples. Neither predicts the future.