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Research-backed, personalized to your numbers. Every article updates with your actual plan data so the math is never hypothetical.
The core math every FIRE plan is built on
Four flavors of financial independence — find which fits your life
How to make a portfolio last 30–50 years
How different spending rules trade off stability and flexibility
A flexible spending band that protects both lifestyle and portfolio
A flexible withdrawal system that supports a higher starting rate
How market valuation at retirement affects your safe withdrawal rate
How probability-based stress-testing works and what success rates mean
Why retirement expenses aren't flat — and what that means for your plan
The claiming age decision is worth hundreds of thousands of dollars
Keep more of what you earn and withdraw efficiently
Which account to fill first and why the order matters
Access your 401(k) before 59½ without the 10% penalty
Which accounts to tap first — and why the order changes your tax bill
The only account with pre-tax contributions, tax-free growth, and tax-free withdrawals
How to keep healthcare affordable between retirement and Medicare
Self-employed savers can shelter nearly triple what W-2 employees can
The inputs behind every projection — and why they matter
Glossary
Short definitions for the terms that appear most often across the app.
Safe withdrawal rate
The starting percentage of your portfolio you can withdraw in year one, then usually inflation-adjust in later years.
CAPE
Shiller's cyclically adjusted price-to-earnings ratio, often used as a rough valuation signal for withdrawal planning.
Coast FIRE
The point where your existing portfolio can compound to your FIRE number by retirement without further contributions.
Sequence risk
The danger that poor returns early in retirement can damage a plan even if long-run average returns end up looking fine.
Methodology
Defaults are transparent starting points, not universal truths.
Real-dollar math by default
The app defaults to inflation-adjusted planning so users can reason in today's purchasing power instead of nominal balances.
A classic first answer, with a safer comparison
A 4% framing gets beginners to a quick answer, while a second comparison rate makes it obvious when a longer FIRE horizon may deserve more margin.
History over flat average-return stories
Historical backtests are emphasized where sequence matters so the app does not imply the market will deliver the same return every year.
Different tools answer different questions
Historical backtests, Monte Carlo, and mortality views stay distinct on purpose so the product remains transparent about what each model is actually saying.
Research
Papers and studies that map directly to the calculators in this app.
Bengen (1994) - SAFEMAX / 4% rule
Historical baseline for fixed real withdrawals and the original 4% framing.
Cooley, Hubbard, Walz (1998) - Trinity Study
Inflation-adjusted stock/bond withdrawal success tables across classic retirement horizons.
Early Retirement Now SWR series
Long-horizon FIRE research, CAPE-based rules, and supplemental cash-flow modeling.
SSA actuarial life table
Longevity assumptions for retirement-duration planning.
Robert Shiller data library
Historical return, inflation, and CAPE data behind valuation-aware analysis.
Guyton & Klinger (2006) - Decision Rules and Maximum Initial Withdrawal Rates
Foundational guardrails paper covering capital-preservation and prosperity rules.
Klinger (2016) - Guardrails to Prevent Potential Retirement Portfolio Failure
Follow-on guardrails research focused on early warning signals and failure prevention.
Early Retirement Now Part 54 - Dynamic withdrawal rates based on CAPE
Practical CAPE-rule implementation, parameter intuition, and long-horizon tradeoffs.
Bogleheads - Variable percentage withdrawal
Community-maintained VPW methodology and table-based implementation notes.
IRS - Required minimum distribution worksheets
Official age-based divisor tables that inform RMD-style withdrawals.
Blanchett (2014) - Estimating the True Cost of Retirement
Empirical spending-decline research behind the retirement spending smile idea.
Morningstar (2025) - The State of Retirement Income
Current research on fixed versus flexible retirement spending approaches.
Retirement Researcher - Floor & ceiling retirement spending strategy
Summary of Bengen's floor-and-ceiling spending-band approach and its tradeoffs.