FIRE Calculator: Financial Independence Retire Early
The FIRE movement (Financial Independence, Retire Early) is built on a simple mathematical truth: the higher your savings rate, the sooner you can retire. Someone saving 10% of their income needs to work roughly 51 years to retire. Save 25%, and it drops to 32 years. At a 50% savings rate, you can retire in about 17 years. At 70%, just 8.5 years. Your FIRE number — the portfolio size that sustains your annual expenses indefinitely — is simply 25 times your annual spending, based on the 4% safe withdrawal rate from the Trinity Study.
The math behind FIRE is unforgiving but empowering. If you spend $40,000 per year, your FIRE number is $1,000,000. If you spend $60,000, it's $1,500,000. Every dollar you cut from annual expenses reduces your required nest egg by $25 and simultaneously increases your savings rate, creating a powerful double effect. This is why FIRE practitioners obsess over expenses rather than income — reducing spending attacks both sides of the equation.
This calculator models your path to financial independence based on your current savings, monthly investment contributions, expected returns, and time horizon. It estimates when you'll hit your FIRE number and how your savings rate affects the timeline. Whether you're pursuing Lean FIRE ($40K/year), regular FIRE, or Fat FIRE ($100K+/year), this tool helps you map the journey.
Key Data & Benchmarks
| Metric | Value |
|---|---|
| FIRE Number (at $40K/yr spending) | $1,000,000 (25x) |
| FIRE Number (at $60K/yr spending) | $1,500,000 (25x) |
| FIRE Number (at $80K/yr spending) | $2,000,000 (25x) |
| 10% Savings Rate → Retire In | ~51 years |
| 25% Savings Rate → Retire In | ~32 years |
| 50% Savings Rate → Retire In | ~17 years |
| 70% Savings Rate → Retire In | ~8.5 years |
| Safe Withdrawal Rate (Trinity Study) | 4% (adjusted annually for inflation) |
Investment Growth Examples
| Scenario | Initial | Monthly | Years | Return | Final Value |
|---|---|---|---|---|---|
| Lean FIRE | $20,000 | $2,000 | 15 | 8% | $748,500 |
| Regular FIRE | $50,000 | $3,000 | 15 | 8% | $1,175,200 |
| Fat FIRE | $100,000 | $5,000 | 15 | 8% | $1,927,400 |
| Coast FIRE (no new contributions) | $250,000 | $0 | 20 | 8% | $1,165,300 |
| Barista FIRE (partial contributions) | $150,000 | $1,000 | 15 | 8% | $831,800 |
Investment Growth Calculator
Who Uses This Calculator?
Calculating your FIRE number
Determine exactly how much you need invested to cover your annual expenses indefinitely using the 25x rule, then track your progress toward that specific target.
Optimizing savings rate
Model how increasing your savings rate by 5-10% accelerates your FIRE timeline. See the dramatic difference between saving 30% vs 50% of your income over a 15-year horizon.
Choosing your FIRE variant
Compare Lean FIRE ($25-40K/year), regular FIRE ($40-80K/year), Fat FIRE ($80K+/year), and Coast FIRE to find the balance between frugality and lifestyle that works for you.
Stress-testing early retirement
Run scenarios with lower return rates (5-6%) or higher spending to see how robust your FIRE plan is against market downturns and lifestyle inflation.
Frequently Asked Questions
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Investment Disclaimer
This calculator is for educational and illustrative purposes only and does not constitute investment advice. All projections use hypothetical constant rates of return that do not reflect actual market conditions. Investments involve risk, including the possible loss of principal. Past performance does not guarantee future results. Consult a qualified financial advisor before making investment decisions.