Methodology

How the planner builds the map.

This page names the math, assumptions, data sources, and review cadence behind The Retirement Atlas planner.

By The Retirement Atlas · Last updated May 29, 2026

Quick read

The planner runs a year-by-year cash-flow model, then tests the same inputs across 1,000 possible market paths. A plan succeeds when savings never deplete before age 95.

Plain English

What the planner does

The planner starts with the household facts a retirement map needs: age, target retirement age, savings, spending, state, filing status, income streams, home details, risk choice, and dreams. It then redraws the road from the current age through age 95. The output is not a verdict. It is a transparent read of what the current numbers are saying.

The math

The core calculation

Base yearly spending

Monthly spending times 12, adjusted for inflation and any spending tier.

Income offset

Social Security, pension, annuity, rental, work, and other income are counted before savings are drawn.

Dream spending

Dreams are modeled as separate yearly costs by default, not hidden inside basic monthly spending.

Savings draw

The engine draws against taxable, tax-free, and pre-tax buckets, then accounts for taxes created by the draw.

Taxes

Federal brackets, Social Security taxability, state tax, RMDs, and Medicare surcharge checks are estimated year by year.

Plan odds

What the market test means

Plan odds are the share of 1,000 tested futures where savings never reach zero before age 95. Each path uses randomized annual returns, randomized inflation, the selected risk level, the household income streams, taxes, required withdrawals, Medicare surcharge checks, and any extra dream spending. The same inputs produce the same result because the random test is seeded.

Paths tested

1,000

Plan end age

95

Success test

Savings stay above $0

Assumptions

The defaults currently used

Assumption
Default
Source
Editable
Plan horizon
Age 95
Engine constant
Editable later through the plan surface
Main return path
Risk pick maps to 4% to 8% nominal return
User risk pick plus engine table
Yes
Moderate default return
6% nominal
Engine default
Yes
Inflation
3% yearly
Engine constant
Yes, where the plan exposes market assumptions
Market tests
1,000 paths
Monte Carlo engine
No
Inflation range in market tests
3% mean with 1.2% volatility
Monte Carlo engine
No
Spending tiers
100%, then 85% at 75, then 75% at 85
Engine default
Yes
RMD age
73 or 75 based on birth year
SECURE 2.0 logic in engine
No, because it follows birth year
Taxable brokerage gain share
50% of taxable withdrawals treated as gain
Engine approximation
Not yet

Data sources

Where the outside numbers come from

Social Security Administration

Social Security claiming rules

Claim age, full retirement age, and benefit timing

Reviewed quarterly and when SSA publishes changes

Internal Revenue Service

Federal tax brackets and standard deduction

Federal income tax estimates

Annual tax-year update

Internal Revenue Service

Required minimum distribution tables

RMD start age and annual divisor math

Reviewed quarterly and when IRS tables change

Medicare and CMS

Medicare premium and IRMAA figures

Medicare surcharge checks in later retirement years

Annual Medicare update

State tax agencies and TRA engine table

State income-tax treatment

State-level retirement tax estimates

Reviewed quarterly and during state-law updates

Stress points

How the cliffs are named

The planner names stress points in plain words. These are not predictions. They are places where the road deserves attention because a common retirement pressure can change what fits.

Road runs short

The plan identifies the age when savings first reach zero before age 95.

A long illness later

The plan uses a care-cost stress point so later-life care does not stay invisible.

A rough first market

The plan calls out the early-retirement years because weak early returns can matter more than weak late returns.

One of them alone

For married households, the plan names the survivor issue because one Social Security check may go away.

Prices rising faster

The plan shows inflation pressure because everyday spending gets first claim.

Review cadence

How the page stays current

Answer pages are reviewed quarterly and whenever SSA, IRS, Medicare, CMS, or state tax updates change a calculation. Annual figures, including federal tax brackets, Medicare premiums, IRMAA brackets, and contribution or distribution thresholds, are updated when the official source publishes the new year.

Current methodology version: v1.0 · Data stamp: May 29, 2026

This plan is educational. It is not personalized financial, tax, or insurance advice. Projections illustrate the math, they do not predict the future. Talk to your own licensed financial professional before acting on any of it.