Early Retirement Calculator - Find Your FIRE Number and Years to Financial Independence
The FIRE movement has shifted from a fringe idea to a mainstream financial goal. The core idea: accumulate a portfolio large enough that investment returns sustainably cover your living expenses. FI Number = Annual Expenses / Safe Withdrawal Rate = Annual Expenses x 25 (at 4 percent).
The Formula Explained
FI Number = Annual Expenses / SWR. Years to FI: solve for n where FI Number = Current Savings x (1+r)^n + Annual Savings x [((1+r)^n - 1) / r].
Worked example: Alex is 32, has $85,000, saves $28,500/year (30 percent savings rate), spends $66,500/year. FI Number: $66,500 / 0.04 = $1,662,500. Alex reaches FI at approximately age 53 to 54.
| Savings Rate | Annual Spending ($80k income) | FI Number | Approx Years to FI |
|---|---|---|---|
| 10% | $72,000 | $1,800,000 | ~46 years |
| 25% | $60,000 | $1,500,000 | ~32 years |
| 40% | $48,000 | $1,200,000 | ~22 years |
| 50% | $40,000 | $1,000,000 | ~17 years |
| 70% | $24,000 | $600,000 | ~10 years |
How to Use This Calculator on CalcAdvisor.com
Run your FIRE calculation at https://www.calcadvisor.com/calculators/early-retirement-calculator.
3 Real-World Examples
Example 1: Mia, 28, Lean FIRE
Mia earns $62,000, spends $32,000/year, saves $25,000/year. FI Number (3.5 percent): $914,286. She reaches it in approximately 17 years - at age 45.
Example 2: Jason and Priya, Fat FIRE With Dual Incomes
Combined $280,000 income, $110,000 expenses, $100,000 savings/year, $320,000 already invested. FI Number: $2,750,000. They reach it in approximately 13 to 14 years - at ages 47 and 46.
Example 3: Derek, 40, Coast FIRE
Derek has $310,000 invested. Full FI Number: $1,450,000. Coast FIRE Number: $267,232. Derek already passed his Coast FIRE Number - he can stop contributing and still reach FI by 65 with zero additional savings.
Common Mistakes to Avoid
- Using pre-retirement spending as your retirement spending without adjusting.
- Ignoring healthcare costs before Medicare eligibility at 65.
- Applying the 4 percent rule to a 50-year retirement without adjustment.
- Not accounting for lifestyle inflation in the spending estimate.
- Treating the FI Number as a finish line rather than a starting point.
- Ignoring the impact of taxes on early retirement withdrawals.
- Not modeling Social Security in a FIRE plan.
Final Thoughts
Start with your numbers today at https://www.calcadvisor.com/calculators/early-retirement-calculator.