What is Financial Independence?
Financial Independence (FI) means having enough invested assets that your portfolio's passive returns can cover your living expenses indefinitely — without needing to work. The FIRE (Financial Independence, Retire Early) movement has popularized this concept, with thousands of people achieving FI in their 30s and 40s by optimizing their savings rate.
The key insight: your time to FI depends almost entirely on your **savings rate**, not your income level. A person earning \$50,000 and saving 50% will reach FI faster than a person earning \$200,000 and saving 10%.
How the FI Number is Calculated
**FI Number** = Annual Expenses ÷ Safe Withdrawal Rate
With a 4% withdrawal rate: \`\`\` FI Number = Annual Expenses × 25 \`\`\`
For example, if you spend \$40,000 per year, you need \$1,000,000 invested.
**Years to FI** is calculated by solving for \`n\` in the compound growth formula: \`\`\` Portfolio(n) = CurrentSavings × (1 + r)^n + AnnualSavings × ((1 + r)^n − 1) / r \`\`\`
Where \`r\` is your expected annual return and \`n\` is the number of years. We solve this iteratively using binary search.
The Safe Withdrawal Rate
The safe withdrawal rate (SWR) is the percentage of your portfolio you can withdraw each year without depleting it. The classic 4% rule (from the Trinity Study, 1998) showed that a 60/40 stock/bond portfolio survived 95%+ of all 30-year historical periods.
**Common SWR choices:** - **4%** — Standard for 30-year retirements - **3.5%** — Conservative for 35–40 year retirements - **3%** — Very conservative for 50+ year retirements (extreme early retirees) - **5%** — Aggressive; better for shorter retirements with flexibility
This calculator defaults to 4%, but you can adjust it for your situation.
Savings Rate and Time to FI
Your savings rate is the single most powerful lever for achieving FI:
| Savings Rate | Years to FI (approx) | |---|---| | 10% | ~43 years | | 25% | ~32 years | | 50% | ~17 years | | 65% | ~11 years | | 75% | ~7 years |
*Assumes 7% return, 4% SWR, starting from zero.*
The FIRE community typically targets a 50–70% savings rate. This often requires significant lifestyle optimization — moving to a lower cost-of-living area, reducing housing costs (house hacking, geo-arbitrage), and eliminating lifestyle inflation.
How to Use This Tool
1. Enter your annual after-tax income 2. Enter your total annual expenses (what you actually spend) 3. Enter your current savings and investments (all accounts) 4. Set your expected annual return (default 7% for a diversified stock portfolio) 5. Set your safe withdrawal rate (default 4%) 6. View your FI number, savings rate, years to FI, and the projected FI date 7. Share your FI date with the "Share My FI Date" button
FAQs
Q: What counts as "savings" in this calculator? A: Include all invested assets: brokerage accounts, 401k, IRA, Roth IRA, index funds, and cash savings intended for investment. Do not include your primary home equity or physical possessions.
Q: Should I use pre-tax or after-tax income? A: Use take-home (after-tax) income, since your expenses come from post-tax dollars. If you're contributing to a pre-tax 401k, add those contributions back into your income for accuracy.
Q: What if my expenses will be different in retirement? A: Use your expected retirement expenses, not current ones. Many people plan for lower expenses in retirement (no commuting, no work clothes, potentially lower housing costs). Enter the number you plan to live on.
Q: Does this account for Social Security? A: No. To factor it in, reduce your annual expenses input by your expected annual Social Security benefit — since you will need to draw less from your portfolio.
Q: Why is my "years to FI" showing 100+? A: This happens when your savings rate is very low or negative (spending more than you earn). The calculator caps at 100 years. To fix this, either increase income, reduce expenses, or both.
Q: What is "coast FI"? A: Coast FI is when your current savings will grow to your FI number on their own by retirement age — even if you stop contributing. This calculator shows full FI (when you can stop working entirely), not Coast FI.
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