FIRE Calculator
How to Use This Tool
Enter your current age, existing savings, yearly income, and annual expenses. Specify your expected real (after-inflation) investment return and safe withdrawal rate (default 4%). Click Calculate to see your projected years to financial independence, retirement age, and required portfolio. Use Reset to clear all fields and start over.
Formula and Logic
The calculator uses iterative year-by-year projection with compound growth. Each year: new portfolio = (previous portfolio × (1 + return)) + annual contribution. It stops when the portfolio reaches the target, calculated as annual expenses ÷ safe withdrawal rate. The safe withdrawal rate represents the percentage you can withdraw annually without depleting your portfolio over a 30-year retirement.
Practical Notes
Key considerations for accurate FIRE planning:
- Real returns matter: Use after-inflation returns (typically 4-7% for a balanced portfolio). Nominal returns will overstate progress if not adjusted for inflation.
- Compounding frequency: We assume annual compounding. More frequent compounding (monthly/quarterly) yields slightly higher returns but the difference is minimal over long horizons.
- Tax implications: This calculator uses pre-tax income and expenses. Actual retirement accounts (401k, IRA, Roth) have different tax treatments. Consider adjusting your target portfolio for taxes—taxable accounts require larger balances than tax-advantaged ones.
- Savings rate is critical: A higher savings rate dramatically shortens time to FIRE. Reducing expenses is often more effective than increasing income alone because it lowers your target portfolio (expenses ÷ withdrawal rate).
- Safe withdrawal rate flexibility: The 4% rule is based on US historical data. In low-return environments or for longer retirements, consider 3-3.5%. For shorter retirements or higher risk tolerance, 5% may be possible.
Why This Tool Is Useful
It transforms abstract retirement goals into concrete, achievable milestones. By quantifying the trade-offs between spending, saving, and investment returns, you can make informed decisions about career choices, lifestyle inflation, and investment allocations. The breakdown shows how much of your future wealth comes from contributions versus investment gains—highlighting the power of compound growth. This clarity helps prioritize financial decisions and stay motivated on your FIRE journey.
Frequently Asked Questions
What if my expenses exceed my income?
You have a negative savings rate, meaning you're accumulating debt. In this scenario, your portfolio will shrink over time, making financial independence impossible unless you increase income or reduce expenses. Focus first on building a positive cash flow before investing for retirement.
How does inflation affect these calculations?
We use real returns (after inflation) so the purchasing power of your target portfolio is already adjusted. If you input nominal returns (before inflation), you must also increase your expense estimates annually by inflation, which complicates the calculation. Using real returns simplifies the model and aligns with the 4% rule's historical basis.
Should I include Social Security or pensions in my calculations?
This calculator excludes external income sources to focus on your personal savings rate and investment portfolio. If you expect Social Security or a pension, subtract those expected annual amounts from your expenses before using this tool. For example, if you expect $20k/year in Social Security and need $50k total, your portfolio only needs to cover $30k.
Additional Guidance
This model assumes stable returns and constant contributions. Real life includes market volatility, job changes, and unexpected expenses. Build a margin of safety by saving more than the minimum or targeting a lower withdrawal rate (e.g., 3.5%). Regularly update your projections as your income, expenses, and market conditions change. Consider using a spreadsheet for more detailed year-by-year modeling that accounts for tax-efficient account sequencing and varying contributions. Remember that FIRE is a framework—flexibility and adaptability are as important as the numbers.