FIRE Calculator: Your Real Financial Independence Number
The 25x rule — multiply your annual spending by 25 to get your FIRE number — is a useful starting point derived from William Bengen’s 1994 research establishing the 4% safe withdrawal rate as a guideline for portfolio longevity. But it makes two assumptions that don’t hold for most people pursuing financial independence: it ignores taxes on withdrawals, and it ignores government benefits. Both of these can materially change your required portfolio size.
If your $70,000 annual spending comes from a traditional RRSP or 401(k), you’re not withdrawing $70,000. You’re withdrawing $90,000-$100,000 and paying $20,000-$30,000 in income tax. That’s closer to 33x your after-tax spending, not 25x. Conversely, if you plan to claim CPP and OAS at 65, those benefits can replace $15,000-$25,000 of annual withdrawals in later years, reducing your required portfolio significantly. A genuine FIRE calculator has to model both sides.
Cinderfi calculates your FIRE number using real tax engines for all 13 Canadian provinces and 50 US states. Enter your target retirement age, expected spending, current savings, and planned account structure, and Cinderfi projects the year-by-year picture including the gap years before government benefits start, the tax cost of withdrawals from each account type, and the portfolio survival probability under different return scenarios.
What Makes Cinderfi Different
- Tax-aware withdrawal modeling: Your FIRE number depends on which accounts you’re drawing from. Cinderfi models RRSP, TFSA, and non-registered (Canada) or Traditional IRA, Roth IRA, and taxable accounts (US) with the correct tax treatment for each.
- Gap year analysis: If you retire at 45 and CPP/OAS (or Social Security) doesn’t start until 65, those 20 years require more from your portfolio. Cinderfi models the transition and shows the impact of different government benefit claiming ages.
- Coast FIRE calculation: Coast FIRE is the portfolio size at which you can stop contributing and the existing balance will grow to your full FIRE number by a target retirement age. Cinderfi shows your coast FIRE number alongside the full number.
- Monte Carlo stress testing: The 4% rule is based on historical US market data. Cinderfi runs 1,000+ simulations with randomized returns to show the probability your plan survives 30, 40, or 50 years — not just the average case.
- Any retirement age: Most retirement calculators are built around age 60-65. Cinderfi supports any retirement age including extreme early retirement scenarios at 35 or 40.
- RRSP meltdown for FIRE: If you’re retiring early with a large RRSP, systematic withdrawals in low-income years before CPP/OAS start can dramatically reduce lifetime taxes. Cinderfi models this strategy automatically.
- Spending flexibility: Model a two-phase retirement where spending is higher in early active years and lower later, or include one-time large expenses like property purchase or children’s education costs.
Find Your Number
Enter your spending, savings rate, and account structure — Cinderfi calculates your real FIRE number with full tax modeling, not just the 25x rule.