Learn FIRE
The FIRE community has no shortage of opinions. What it sometimes lacks is the underlying math. These guides cover the actual mechanics — where the 4% rule came from, what the Trinity Study does and does not prove, why Coast FIRE is less about frugality and more about compounding timelines, and how to read a Monte Carlo result without panicking at a 72% success rate.
The calculators on this site give you numbers. These posts explain what those numbers mean.
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what is FIRE movement
What Is the FIRE Movement? A Complete Guide to Financial Independence
Learn what the FIRE movement is, how it works, the main types of FIRE, and the practical first steps to start pursuing financial independence.
4 percent rule retirement
The 4% Rule Explained: Is It Still Safe for Early Retirees?
Understand where the 4% rule comes from, how it works, why early retirees may prefer lower withdrawal rates, and how Monte Carlo analysis improves the conversation.
how to calculate FIRE number
How to Calculate Your FIRE Number in 5 Minutes
Learn the simple FIRE number formula, how to estimate spending, choose a withdrawal rate, account for Social Security, and apply inflation intelligently.
coast fire number by age
Coast FIRE Number by Age: What You Need at 25, 30, 35, and 40
See exactly how much you need invested at every age so compound growth carries your portfolio to full FIRE by retirement — with no further contributions.
what is barista fire
What Is Barista FIRE? A Complete Guide to Semi-Retirement
Barista FIRE lets you leave full-time work years earlier by combining part-time income with a smaller portfolio. Learn the math, the risks, and whether it fits.
fire calculator with social security
FIRE Calculator with Social Security: How to Model the Bridge Years
Most FIRE calculators ignore Social Security. Learn how to model the bridge period between early retirement and benefits — and why it changes your FIRE number.
safe withdrawal rate 40 year retirement
Safe Withdrawal Rate for a 40-Year Retirement: What the Research Actually Says
The 4% rule was built for 30-year retirements. For 40+ years, the research points to 3.25–3.5%. Here is what Bengen, the Trinity Study, and modern analysis found.
lean fire vs fat fire
Lean FIRE vs Fat FIRE: Which Strategy Fits Your Life?
Lean FIRE targets $625k–$1M; Fat FIRE starts at $2.5M. Compare the math, risk profiles, income requirements, and lifestyle tradeoffs side by side.
what is fat fire
What Is Fat FIRE? How Much You Need and How to Get There
Fat FIRE means $100k+ per year in retirement — no lifestyle downgrade. Learn the portfolio math, accumulation paths, healthcare planning, and sequence risk at scale.
monte carlo simulation retirement planning
Monte Carlo Simulation for Retirement: What It Actually Tells You
A Monte Carlo simulation runs 1,000 hypothetical retirements. Learn what the survival percentage actually measures, where it misleads, and how to read results.
savings rate fire retirement
Savings Rate and FIRE: The Math Behind Early Retirement
Your savings rate determines your FIRE timeline more than returns do. See the exact math, tables by savings rate, and why the double effect makes it the dominant variable.
how much to retire early
How Much Do I Need to Retire at 40, 45, 50, or 55?
See the exact portfolio you need to retire early at every age, using the 4% rule and adjusted withdrawal rates for 30–50 year retirements.
best fire calculators
Best FIRE Calculators in 2026: Free Tools Compared
Compare the top free FIRE calculators side by side: features, accuracy, Monte Carlo support, and which one fits your planning style.
personal savings rate
Personal Savings Rate: Why It Beats Investment Returns
Your savings rate determines your retirement timeline more than market returns. See the math, benchmarks by income, and how to calculate yours correctly.
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