Your FIRE number is the size of portfolio that lets a safe annual withdrawal cover your living costs indefinitely. At a 4% withdrawal rate, that number is simply your annual spending multiplied by 25. Spend $40,000 a year and your FIRE number is $1,000,000; spend $60,000 and it’s $1,500,000. Everything else in financial independence — your savings rate, your investments, your timeline — is in service of reaching that one figure.
You can find yours in seconds with the FIRE Number & Years-to-FI Calculator. This article explains where the number comes from and, more usefully, how to reach it years sooner.
Why the multiple is 25
The 25x rule is the mirror image of the 4% rule. If you can safely withdraw 4% of a portfolio each year, then the portfolio you need is 100% ÷ 4% = 25 times your annual withdrawal. The 4% figure comes from decades of US market history showing that a 4% inflation-adjusted withdrawal survived almost every 30-year period on record. (We dig into the caveats in The 4% Rule in 2026.)
Change the withdrawal rate and the multiple changes with it:
| Safe withdrawal rate | Multiple of spending | FIRE number on $40k/yr |
|---|---|---|
| 5.0% | 20x | $800,000 |
| 4.0% | 25x | $1,000,000 |
| 3.5% | ~28.6x | $1,143,000 |
| 3.0% | ~33.3x | $1,333,000 |
A more cautious withdrawal rate buys safety but raises the bar. Most people in the FIRE community start the conversation at 4% / 25x and adjust from there.
Step 1: Nail down your real spending
The single biggest input is your annual spending in retirement, not your income. Two people earning the same salary can have FIRE numbers that differ by hundreds of thousands of dollars purely because one spends more. Track your actual expenses for a few months, then adjust for what changes in retirement: no commuting or payroll taxes, but possibly higher health-care costs.
A subtle but powerful point: cutting a recurring expense lowers your FIRE number by 25 times the annual saving. Trimming a $200/month subscription habit ($2,400/yr) cuts your target by $60,000. That’s why frugality is such a potent FIRE lever — it works on both sides of the equation.
Step 2: Subtract guaranteed income (optional)
If you expect Social Security, a pension or rental income in retirement, you don’t need your portfolio to fund everything. Subtract that guaranteed income from your annual spending before multiplying by 25. For example, $50,000 of spending minus $20,000 of expected Social Security leaves $30,000 to fund from your portfolio — a FIRE number of $750,000 rather than $1,250,000. Our calculator targets full portfolio coverage by default, so treat this as a manual adjustment.
Step 3: Find your years-to-FI
Once you know the target, the question becomes how long. That depends on three things: how much you’ve already saved, how much you add each year, and your real (after-inflation) return. The FIRE Number Calculator projects your balance forward year by year until it reaches the target.
Here’s the part that surprises people: your savings rate matters far more than your return. Your savings rate — the share of take-home pay you invest — sets both how fast you accumulate and how little you need to live on. The table below shows roughly how many years to financial independence at different savings rates, starting from zero and assuming a 5% real return:
| Savings rate | Approx. years to FI |
|---|---|
| 10% | ~51 years |
| 25% | ~32 years |
| 50% | ~17 years |
| 65% | ~10.5 years |
Doubling your investment return might shave a few years off; doubling your savings rate can cut your timeline in half. That’s because a higher savings rate is a double win: more money invested and a smaller number to hit.
The levers, ranked
- Savings rate. The dominant factor. Every percentage point you save is a point you don’t have to fund forever.
- Spending. Lower spending shrinks the target by 25x the annual cut and frees cash to invest.
- Capturing free money. Don’t skip your employer 401(k) match — see 401(k) Match: Don’t Leave Free Money. It’s an instant return that accelerates everything.
- Tax efficiency. Choosing the right account (see Roth vs Traditional: Which Wins?) and using 2026’s higher contribution limits keeps more of your money compounding.
- Investment return. Real, but the least controllable — and chasing it adds risk.
A worked example
Say you spend $48,000 a year and want a 4% withdrawal rate.
- FIRE number: $48,000 × 25 = $1,200,000.
- Today: $80,000 invested, adding $30,000/year, expecting a 6% real return.
- Plugging that into the calculator returns roughly 20 years to financial independence.
Now bump the contribution to $45,000/year (a higher savings rate) and the timeline drops to about 15 years — five years bought with discipline, not luck. If you’re not quite ready to retire fully but want to stop adding new money, check whether you’ve hit Coast FIRE instead.
A note on inflation and honesty
Use a real (after-inflation) return — typically 4–7% for a stock-heavy portfolio — so your projection stays in today’s dollars and your FIRE number keeps its meaning. And remember these are planning estimates, not financial advice. Markets are volatile, the early years of retirement carry sequence-of-returns risk, and tax law changes. Verify contribution limits with the IRS and talk to a qualified professional before making big moves.
Your FIRE number is one multiplication away. The years-to-FI part is where the real work — and the real freedom — lives.