Lean FIRE vs Fat FIRE Calculator
Compare the nest egg needed for Lean, Regular, and Fat FIRE based on your spending tiers and the 4% rule. Runs in your browser.
Nest egg by tier (25× spending)
| Tier | Annual spend | Nest egg |
|---|---|---|
| Lean FIRE | $30,000 | $750,000 |
| Regular FIRE | $55,000 | $1,375,000 |
| Fat FIRE | $120,000 | $3,000,000 |
Each tier's nest egg = annual spending ÷ withdrawal rate (25× at 4%). Lean FIRE = a frugal, minimalist budget; Regular = a typical comfortable lifestyle; Fat FIRE = an abundant, no-compromises budget. Higher spending requires a proportionally larger portfolio. Informational, not financial advice.
About this tool
Financial independence is not one number — it depends entirely on the lifestyle you want to fund. This calculator contrasts three common tiers. Lean FIRE is a frugal, minimalist retirement on a tight budget; Regular FIRE supports a typical comfortable middle-class lifestyle; and Fat FIRE funds an abundant, no-compromises budget with travel, dining, and margin to spare. For each tier you enter the annual spending, and the tool applies the safe-withdrawal rule (a portfolio of spending ÷ withdrawal rate, i.e. 25× at 4%) to show the nest egg required. Seeing them side by side clarifies the trade-off at the heart of FIRE: because the target scales directly with spending, choosing a leaner lifestyle can cut the required portfolio — and the years of work to reach it — by hundreds of thousands of dollars, while Fat FIRE demands a much larger sum and a longer or higher-earning path. Use a conservative withdrawal rate for early or long retirements. It is informational, not financial advice. Everything runs in your browser.
How to use it
- Enter the annual spending for a lean, regular, and fat lifestyle.
- Set the safe withdrawal rate (4% is standard; 3–3.5% is more conservative).
- Compare the nest egg each tier requires.
- Use it to pick a target lifestyle and see its cost in portfolio terms.
Frequently asked questions
- What are Lean, Regular, and Fat FIRE?
- They are spending tiers. Lean FIRE funds a frugal, low-cost lifestyle; Regular FIRE a typical comfortable one; Fat FIRE an affluent budget with plenty of discretionary spending. The names describe the lifestyle, and each implies a different nest egg.
- How is each nest egg calculated?
- Annual spending ÷ safe withdrawal rate. At 4%, that is 25× spending: Lean FIRE on $30k needs $750k, Fat FIRE on $120k needs $3M. A lower withdrawal rate raises the multiple (e.g. 33× at 3%).
- Why does the target scale so directly with spending?
- Because the safe-withdrawal rule ties the portfolio to spending: every extra $1,000 of annual spending adds $25,000 to the target at 4%. That linear relationship is why frugality is the fastest route to a smaller, sooner-reached number.
- Which tier should I aim for?
- It is personal — a balance between the lifestyle you want and how long you are willing to work to fund it. Many people target Regular FIRE; some accept Lean FIRE to retire much sooner, while higher earners pursue Fat FIRE. There is no single right answer.
- Should I use 4% for all tiers?
- You can, but consider a more conservative rate (3–3.5%) for very early retirements or long horizons, which raises every tier's target. Fat FIRE retirees sometimes use a lower rate for extra safety given the larger sums involved.
- Is this financial advice?
- No. It is an informational comparison. Consult a financial advisor for a personalized plan.