Disclaimers & Methodology

Educational purposes only — not financial advice

These tools are provided for educational and illustrative purposes only. They are not financial, investment, tax, or legal advice. Results are estimates based on simplified models and should not be used as the basis for financial decisions. Consult a qualified financial professional before making any significant financial choices.

Your data stays on your device

We do not collect, store, or transmit any of your personal financial information to our servers. All data you enter is saved locally in your browser using localStorage to preserve your calculations between visits. For your privacy, avoid entering sensitive personal information such as full legal names, Social Security numbers, or account numbers.

How the planner calculates

Retirement number — Your savings target, calculated as 25× your annual expenses (the 4% rule). This is the point where a 4% annual withdrawal covers your costs indefinitely under average market conditions.

Range of Outcomes — Rather than a single projected path, the planner runs 500 simulated market scenarios using log-normal returns. The shaded band shows the middle 80% of possible outcomes; the line is the most likely path. All values are shown in today’s dollars, adjusted for 3% annual inflation.

Market scenarios — Three growth assumptions drive the simulation:

Bear (conservative): 5% while working, 3% in retirement, 12% annual volatility
Base (moderate): 8% while working, 5% in retirement, 10% annual volatility
Bull (optimistic): 11% while working, 7% in retirement, 14% annual volatility

Social Security — Expected monthly benefits offset portfolio withdrawals from your chosen claiming age. Benefits are inflation-adjusted in the projection. Figures are self-reported — verify your actual estimate at ssa.gov.

Retirement trigger — Decumulation starts at your chosen retirement age, regardless of portfolio balance. The 25× number is a planning benchmark, not a trigger.

Simplifying assumptions

Log-normal return distributions are an approximation. Real markets have fatter tails — crashes and booms can be more extreme than the model expects.
Inflation is modeled at a flat 3% annually. Actual inflation varies.
The 25× retirement number (4% rule) is a guideline, not a guarantee. It has held historically but may not in all future market environments.
Taxes on withdrawals are not modeled. Distributions from 401(k)s, traditional IRAs, and taxable accounts are generally subject to income tax.
Contribution limits (401k, IRA), healthcare costs in retirement, and means-tested benefit reductions are not modeled.
Program rules (withdrawal ages, Social Security, etc.) can change; verify current rules for your situation.

How to use responsibly

Run all three market scenarios. Bear shows what happens if markets underperform; Bull shows the upside. The gap between them is your real uncertainty range.
Pay attention to the “Likelihood your money lasts to 100” percentage — a low number signals meaningful longevity risk even in the most likely path.
Use results to generate better questions for a financial professional, not as final answers.