FIRE Path Explorer

Turn financial independence into three numbers

FIRE (Financial Independence, Retire Early) planning boils down to a target, a timeline, and a milestone. The target is your FIRE number. The timeline is when steady investing could reach it. The milestone is Coast FIRE, the point where growth alone can finish the job. This explorer computes all three from five inputs and shows the path on one chart.

How the explorer works

Everything starts from spending, not income. Your FIRE number is your annual spending divided by the initial withdrawal rate you select, so at 4% the target is 25 times spending. The projection then grows your current portfolio at the expected real return and adds your contribution at the end of each year until the balance crosses the target.

Example walkthrough

Same defaults as the tool: $40,000 annual spending, $100,000 invested, $12,000 contributed per year, 5% real return, 4% withdrawal rate.

① FIRE number
   $40,000 ÷ 4% → $1,000,000

② Project the portfolio year by year
   $100,000 growing at 5% real, plus $12,000 each year
   → crosses $1,000,000 in about 27 years

③ Coast FIRE amount
   $1,000,000 discounted back 27 years at 5%
   → about $268,000 invested today would coast there

• Step 1 sets the goal line on the chart. Because it is built from spending, cutting expenses lowers the target and shortens the timeline at once.
• Step 2 is the estimated financial independence year: the first projected year the balance reaches the FIRE number.
• Step 3 answers a different question: how much would already be enough today if you stopped contributing and just let compounding run the same clock.

Where the withdrawal-rate research comes from

The 4% starting point traces to William Bengen's 1994 study Determining Withdrawal Rates Using Historical Data, which tested inflation-adjusted withdrawals against historical U.S. market returns over 30-year retirements. Morningstar's retirement-income research revisits that figure regularly, and its safe starting rate moves with assumptions about time horizon, portfolio allocation, inflation, and how flexible your spending can be. Longer early retirements generally argue for a lower initial rate, which is why the tool lets you compare several.

What the model deliberately leaves out

This is an educational planning tool, not personal financial advice. It assumes a smooth constant return, while real markets deliver volatile ones, and it does not model taxes, investment fees, pensions, social security, windfalls, or the way your spending will change over decades. No output here is a promise or a guaranteed retirement date. Use it to understand the shape of the journey, then revisit with real numbers as they change.