FIRE Number Calculator
Your numbers
Three fields. Everything else is pre-filled from real data — and editable below.
What you'd actually spend per year, in today's dollars — housing, health insurance, everything
Retirement accounts + brokerage. Don't count home equity or your emergency fund
What you add across all investment accounts each month — $0 is allowed
How we calculate this
Your FIRE number is your annual retirement spending divided by a safe withdrawal rate. At the standard 4% rate that works out to 25× your annual spending — the "25× rule." The 4% figure comes from William Bengen's 1994 research and the Trinity study (1998), which found a portfolio could survive 30 years of inflation-adjusted withdrawals at that rate through the worst market sequences in US history.
Retiring decades early stretches that 30-year assumption, which is why we offer two alternatives: 3.9%, the rate Morningstar's 2025 research supports at 90% confidence for a 30-year retirement, and 3.5%, the common planner guidance for 40–50 year early-retirement horizons.
Your timeline comes from growing your current portfolio at a real (inflation-adjusted) return — 6.9% by default, the historical US stock average from NYU Stern's data — with your monthly contributions added at the end of each month, compounded monthly. Because the return is already inflation-adjusted, every figure on this page is in today's dollars: no mental math converting future amounts back to what they'd actually buy.
Your Coast FIRE number is your FIRE number discounted back from traditional retirement age (67 by default — the Social Security full retirement age) at the same return. It's the portfolio size where you could stop contributing entirely and let growth alone finish the job.
What we deliberately don't model: taxes on withdrawals (that depends on your Roth/traditional/brokerage mix), sequence-of-returns risk (the withdrawal rate itself is the safety margin for bad early years), Social Security (treat it as an extra buffer), and spending changes in retirement. The assumptions panel above says all of this next to your result, too.
Real scenarios
Mid-career starter: 34, average savings, steady pace
A 34-year-old spending $65,000 a year in retirement needs $1,625,000 at the 4% rule. With $120,000 already invested and $1,800/month going in, they reach it in about 22 years — financially independent around age 56, a full decade before traditional retirement.
Lean spender, aggressive saver: FI in under 10 years
Someone who can live on $40,000 a year needs just $1,000,000. Starting from $200,000 invested and saving $4,000/month, they hit that in roughly 9.3 years. Spending is the lever that works twice: every dollar cut from the budget shrinks the target and frees up more to invest.
The price of a safer withdrawal rate
A $60,000/year spender with $100,000 invested and $2,000/month saved reaches the 4% target of $1.5M in about 20.7 years. Switching to the conservative 3.5% rate raises the target to $1,714,286 — about 19 more months of saving. For a retirement that might last 45 years, that's cheap insurance.