Lean FIRE Calculator
Retire early on a frugal lifestyle — typically $25–40k/yr. Because you spend less, your required portfolio is smaller and you reach financial independence faster. Find your number and date, free and instant.
Lean FIRE is early retirement on a frugal, low-spend budget — typically under $40,000 per year. It requires the smallest portfolio of any FIRE type, making it the fastest path to financial independence for people willing to live minimally.
See the formula & example
Lean FIRE number = annual spending ÷ safe withdrawal rate. At $25,000/yr with a 4% rate, your target is $625,000. Many Lean FIRE practitioners use 3.75% for extra safety over a long retirement. Enter your numbers above to see your personal target.ⓘ Educational estimates based on your inputs — not financial advice.
How Lean FIRE works
Lean FIRE uses the standard formula: FIRE number = annual spending ÷ safe withdrawal rate. Because Lean FIRE spending is typically $25,000–$40,000/yr, the required portfolio is $625,000–$1,000,000 — far smaller than Standard or Fat FIRE. Many Lean FIRE practitioners use a 3.75% withdrawal rate (rather than 4%) for extra safety over a potentially 50+ year retirement.
The lower your annual spending, the smaller your number and the faster you reach it. Dropping spending from $40,000/yr to $30,000/yr cuts your FIRE number by $250,000 at a 4% SWR — often equivalent to several extra years of saving.
Lean FIRE worked example
Jordan is 28, has $25,000 invested, saves $18,000/yr from a $48,000/yr income (37.5% savings rate), and plans to retire on $24,000/yr. At a 3.75% SWR, Jordan's Lean FIRE number is $640,000. With 7% real returns, Jordan reaches it by age 44 — 21 years of working, then financial independence for life.
Lean FIRE target by spending level
| Annual spending | FIRE number (4% SWR) | FIRE number (3.75% SWR) |
|---|---|---|
| $20,000/yr | $500,000 | $533,333 |
| $25,000/yr | $625,000 | $666,667 |
| $30,000/yr | $750,000 | $800,000 |
| $35,000/yr | $875,000 | $933,333 |
| $40,000/yr | $1,000,000 | $1,066,667 |
Lean FIRE vs other FIRE types
| Type | Annual spending | Target portfolio | Lifestyle |
|---|---|---|---|
| Lean FIRE | Under $40,000/yr | $625k–$1M | Frugal, intentional, minimalist |
| Standard FIRE | $40,000–$100,000/yr | $1M–$2.5M | Typical middle-class comfort |
| Fat FIRE | $100,000+/yr | $2.5M+ | High-spend, no compromises |
| Barista FIRE | Any level | Reduced by part-time income | Semi-retired, flexible |
| Coast FIRE | Any level | Lump-sum today, then coast | Work optional before traditional retirement |
Pros and cons of Lean FIRE
Pros:
- Smallest portfolio requirement — fastest path to financial independence
- Forces intentional spending habits that often increase life satisfaction
- More resilient than larger targets: sequence-of-returns risk is lower with a smaller portfolio
- Pairs well with geographic arbitrage (lower cost-of-living countries or regions)
Cons:
- Less spending flexibility — unexpected costs (medical, family) can stress the budget
- Social pressures if lifestyle differs significantly from peers
- May need to return to work if spending creeps up or returns disappoint
Lean FIRE — frequently asked questions
What is Lean FIRE?
Lean FIRE is early retirement on a frugal, intentional lifestyle — typically spending $25,000–$40,000 per year. Because you need less from your portfolio, your required savings target is much smaller ($625k–$1M at 4%), making it achievable faster even on a modest income.
How much do I need for Lean FIRE?
Using the Rule of 25 (4% withdrawal rate): $25,000/yr needs $625,000. $30,000/yr needs $750,000. $40,000/yr needs $1,000,000. Many Lean FIRE planners use 3.75% for a longer retirement horizon. Enter your exact spending above for your personal number.
What is the difference between Lean FIRE and Standard FIRE?
Lean FIRE means retiring on under $40,000/yr — a frugal, intentional lifestyle. Standard FIRE covers $40,000–$100,000/yr (typical middle-class). Fat FIRE is $100,000/yr or more. The calculator auto-detects your tier from your spending level.
Is Lean FIRE realistic?
For many people, yes — especially with low housing costs, no debt, and health. The challenge is sustaining low spending for decades and handling unexpected expenses. Building a small buffer above your target (2–3 years of expenses) significantly improves resilience. Geographic arbitrage (living in lower-cost areas) can make Lean FIRE comfortable and sustainable.
Can I do Lean FIRE and Coast FIRE at the same time?
Yes. Coast FIRE is a strategy for reaching your number — including a Lean FIRE number. If you save aggressively early and hit your Coast FIRE point for a $650,000 Lean FIRE target, you can stop contributing and let the portfolio grow. You still need to live on low spending in retirement, but you can ease off saving years before you actually stop working.