How Many Years Until You Can Retire?
Enter your monthly expenses, savings, monthly savings, and expected return rate to calculate your FIRE number and exactly how many years until you can retire.
Your retirement target = annual expenses × 25 — that's the portfolio that can sustain you indefinitely on the 4% rule.
25×
your annual expenses is the FIRE number — the portfolio needed to retire on the 4% rule
15 yr
typical FIRE timeline for someone saving 50%+ of income starting in their 30s
4%
safe withdrawal rate — the annual % you can take from your portfolio indefinitely
The math behind financial independence
Your FIRE number is just expenses × 25
The simplicity of the 4% rule is what made it powerful. Annual expenses × 25 = your target portfolio. The math works because a 4% annual withdrawal from a 7%-returning portfolio leaves 3% to offset inflation and portfolio growth. Keeping expenses low has a compounding double benefit: smaller FIRE number AND more money available to invest each year.
Savings rate is the key variable
Traditional retirement advice (save 10–15% of income) leads to retiring at 60–65. Saving 25% gets you there in 32 years. Saving 50% in 17 years. Saving 75% in under 10 years. The relationship is highly non-linear: small increases in savings rate early in your career have outsized effects on retirement age. Starting a few years earlier matters far more than investment returns.
Build flexibility into your plan
Most FIRE practitioners build a buffer: targeting 3.5% withdrawal rate (FI number = expenses × 28.5), having part-time or side income to supplement in early retirement years, and keeping 1–3 years of expenses in cash/bonds to avoid selling stocks in a downturn. The 4% rule works — but building in margin of safety improves resilience against sequence-of-returns risk.
How the Time to Retirement Calculator Works
Formula
FIRE Number = Monthly Expenses × 12 × 25\nMonthly Return = Annual Return ÷ 12\nBalance grows month by month until ≥ FIRE NumberThe calculator uses the 4% safe withdrawal rate to derive your retirement target (expenses × 25). It then simulates monthly compounding: each month your existing savings grow by the monthly return rate, and your monthly contribution is added.
The loop continues until the projected balance reaches your FIRE number. The result is the number of years and months from today until financial independence at your current savings rate and assumed return.