Coast FIRE Guides

Short, honest explainers - each one links straight into the calculator so you can run your own numbers.

The basics

The basicsACA Subsidies for Early Retirees: The Income Cliff Explained (2026)Early retirees buy health insurance on the ACA marketplace, where subsidies depend on MAGI. As of 2026, the 400% federal-poverty-level subsidy cliff is back. Here's how income management works and why it matters.8 min read The basicsRoth Conversion Ladder: How Early Retirees Reach Pre-59½ MoneyA Roth conversion ladder lets early retirees tap tax-deferred savings years before 59½ without the early-withdrawal penalty. Here's the mechanism, the 5-year rule, and where it can go wrong.8 min read The basicsHow Much Do I Need to Retire Early? The 25x Rule, Step by StepThe 25x rule says your number is your annual spending times 25. Here's where that 25 comes from, a worked example with real arithmetic, and why the single flat multiple is a simplification worth understanding.7 min read The basicsBarista FI vs Coast FI vs Lean FI vs Fat FI: Definitions and NumbersLean, Fat, Coast, and Barista FIRE are four different answers to two different questions: how big is your number, and do you keep working while you get there. Here's what each term means and where they actually differ.7 min read The basicsEmergency Fund Size for FIRE: Why 3-6 Months Isn't the Whole AnswerThe standard 3-6 months of expenses rule was built for a stable W-2 paycheck. If you're pursuing or coasting toward FIRE, the right number depends on your income stability, your portfolio's real liquidity, and how close you are to the point of no more saving.8 min read The basicsSavings Rate vs. Investment Returns: Which Moves Your Number More?A higher savings rate and a higher return both pull your Coast FI age earlier, but not the same way. Here's what the real math shows about which lever swings your projection more, and why.7 min read The basicsWhat Is Coast FIRE? The Point Where Your Savings Finish the JobCoast FIRE is the moment your invested savings are big enough to grow into full retirement on their own - no new contributions needed. Here's how to find that point, and why it's a probability, not a date.7 min read The basicsIs Coast FIRE Risky? Sequence of Returns and CoastingCoast FIRE front-loads your savings, then lets growth do the rest - which means the order returns arrive in matters more than their average. Here's what that risk actually looks like.9 min read

Data deep dives

Data deep divesThe 4% Rule in 2026: What 150 Years of Data Actually ShowsThe 4% rule is the most quoted number in early retirement, and almost nobody checks it. We ran a fixed 4% real withdrawal through every 30-year window in 155 years of US market history. It survived 97.9% of the time - and the failures tell a sharper story than the headline.10 min read Data deep divesHow Long Will $2 Million Last in Early Retirement? The Fat FIRE AnswerAt $2 million, the question stops being whether the money lasts and becomes how much you can comfortably spend, and whether the extra years you worked to get here were worth it. Here is how long $2 million actually lasted at $60k, $80k, $100k, and $120k a year across 150 years of US market history, and what it reveals about the one-more-year trap.6 min read Data deep divesHow Long Will $500,000 Last in Early Retirement? The Lean FIRE AnswerStraight-line math says $500k at $20k a year lasts 25 years. Real US market history says the median window lasted the full 40-year test, while the worst ran dry in 16.6 years. Here is how long $500,000 actually lasted at $20k, $30k, and $40k a year, and why part-time income moves the odds more than the balance does.6 min read Data deep divesHow Long Will $1 Million Last in Early Retirement? The Historical AnswerStraight-line math says $1M at $40k a year lasts 25 years. Real US market history says the median window lasted the full 40-year test - and the worst ran dry in 16.6 years. Here's how long $1 million actually lasted at $40k, $60k, $80k, and $100k of annual spending.6 min read Data deep divesWe Played 10,000 Financial Lives for Each Strategy. Diversification Had the Best Odds Every Time.We built a financial-life game, then ran 10,000 seeded lives for each of thirteen strategies. The diversified one had the highest win rate in every starting scenario. The concentrated bets kept the biggest jackpots and the fastest deaths. Here is the full win-rate table and the honest caveats.9 min read Data deep divesWe Simulated 19,591 Market Timers Across 150 Years. Nearly Three in Four Lost.We built a population of behavioral market-timers, panic sellers, drawdown dodgers, coin flippers, and momentum chasers, and ran every one of them across every 30-year window since 1871. Only 28.4% beat an investor who just bought every month and never sold.8 min read Data deep divesCan You Time the Market? What 150 Years of Data SayMissing the market's best months, buying every dip, timing it perfectly, and leaning on leverage all sound smart. Across every 30-year window since 1871, here is what they actually did to real wealth.9 min read Data deep divesMonte Carlo Retirement Simulation: What It Is and What It Gets WrongA Monte Carlo retirement simulation runs your plan through thousands of possible futures instead of one straight-line average. Here's what that actually means, and the three different engines behind it that most calculators never disclose.8 min read Data deep divesSafe Withdrawal Rate History: Every 30-Year Window Since 1872We backtested every real 30-year retirement window in 154 years of US market history. Here's exactly how often a 3%, 4%, 5%, or 6% withdrawal rate actually lasted the full 30 years - no simulation, no resampling, just real history.8 min read Data deep divesWhy a US-Only Portfolio Underperforms a Diversified One (A Fair, Same-Years Test)Tested against the exact same historical years, a diversified portfolio beat an all-US one for retirement survival: 100% success versus 94.9% over 1991-2025. Here's the fair, apples-to-apples comparison, and the honest caveats behind it.7 min read

Cost comparisons

Cost comparisonsWealthfront vs Betterment vs DIY: What the Fees Cost Over 30 YearsAs of July 2026, Wealthfront and Betterment both charge 0.25% a year and a DIY index fund about 0.03%. In an illustrative backtest across 150 years of real US market returns, the robo tier cost a typical saver about $59,000 versus DIY over 30 years, and a 1% human advisor about $199,000. Here is where that money goes, and when paying it is still worth it.8 min read

Coast FIRE number by age

How much you need invested to coast - worked out for a representative saver at each age.

At 25 At 30 At 35 At 40 At 45