Five assets, five real returns, one FIRE number. This basic version models the core household balance sheet — cash, equities, bonds, Bitcoin, and your primary residence. If you have anything more complex (HSA, 529, I-bonds, rental properties, annuities, private real estate), the intermediate and advanced versions add those.
Want more asset categories? Intermediate (12 assets) → · Advanced (35 assets) →
💰 Cash / High-Yield Savings
📈 Equities / Index Funds
📄 Bonds / Fixed Income
₿️ Bitcoin
🏠 Real Estate (Primary Residence)
Methodology: Returns are real (inflation-adjusted), compounded monthly. The 4% safe withdrawal rate comes from the 1998 Trinity Study. Read the full methodology → · What we don’t model: volatility distribution, sequence-of-returns risk, tax drag, healthcare inflation, Social Security, primary residence as withdrawal source (most retirees don’t sell their house).
Frequently asked questions
Why only 5 assets?
Most household balance sheets fit in these five categories. This basic version is designed for the “I’ve heard of the 4% rule but never modeled a retirement scenario” user. If you have an HSA, 529, I-bonds, rental properties, annuities, or other assets, the intermediate (12 assets) and advanced (35 assets) versions cover those.
Should I include my primary residence?
It’s your call. The honest answer is that most retirees don’t sell their house to fund retirement, so including it inflates the retirement number on paper without giving you spendable income. If you plan to downsize at retirement, include only the equity you’ll actually convert to cash. If you plan to age in place, set the real return to 0% (your house preserves value but doesn’t fund withdrawals).
Are these returns nominal or real?
Real — inflation-adjusted. The future portfolio value shown is in today’s purchasing power. The defaults are conservative-to-mainstream: 0.5% cash, 7% equities, 1.5% bonds, 12% Bitcoin, 3% real estate. Override any of them based on your own assumptions.
Why 4% safe withdrawal rate?
The 4% rule comes from the 1998 Trinity Study. It estimates the annual withdrawal you can safely take from a portfolio with a high probability of the money lasting 30+ years. Newer research (Wade Pfau and others) suggests 3-3.5% is more conservative for current valuations. You can adjust the SWR field above. Sequence-of-returns risk is the biggest reason to consider going lower.
What’s the “FIRE number”?
It’s the portfolio size needed to retire and live off withdrawals indefinitely. The standard formula: annual spending divided by your SWR. So $60,000 / year spending at a 4% SWR = $1,500,000 FIRE number. This calculator shows your projected future portfolio — compare it to your own FIRE number to see if you’re on track.
Three other things to try
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