Your "enough" number — the amount that lets you stop working, if you want to — is typically your annual spending divided by your safe withdrawal rate, commonly expressed as roughly 25 times your annual expenses (at a 4% withdrawal rate). But the number is only half the answer; what it costs you to get there matters just as much as the number itself.
Most FI content treats "the number" as a purely mathematical target. It is math — see our FI number calculator to compute yours — but the more interesting question is usually the one underneath it: enough for what, exactly?
Your number is actually two numbers
- The math number. Annual spending ÷ safe withdrawal rate. Mechanical, calculable, and it's what most calculators (including ours) give you.
- The lifestyle number. What annual spending figure you actually plug into that formula. This is the one people skip, and it's the one that actually determines whether your "enough" is realistic or a fantasy built on a bare-bones budget you wouldn't actually want to live on.
Two people can have wildly different real "enough" numbers with the same income, purely because they define their lifestyle number differently. Neither is wrong — but pretending your number is smaller than your actual desired lifestyle just moves the disappointment to after you've already quit.
Lifestyle creep moves the target
Because the number is a multiple of spending, lifestyle inflation doesn't just cost you the extra spending today — it moves your entire target further away. An extra $500/month in permanent new spending doesn't just cost $500/month; at a 4% withdrawal rate, it adds $150,000 to your total number ($500 × 12 ÷ 0.04). This is why the Save pillar content on this site focuses on permanent, structural savings changes rather than one-time cuts — a permanently lower baseline spend is the only kind of change that actually shrinks the target instead of just working harder to hit a moving one.
"Enough" isn't a fixed, one-time target either
Your number when you're 25 and childless is a different number than at 40 with a mortgage and kids, and it may change again after that. Treating your FI number as a milestone to hit once, rather than a figure to revisit as your actual life and spending change, is one of the more common ways people either burn out chasing an outdated target or under-save against a target that quietly grew.
Calculate your actual number
Enter your real spending, savings rate, and timeline to see your own FI number and how many years of investing stand between you and it.
Use the FI number calculatorBest budgeting apps
A good budgeting app makes this easier to actually track — see our current picks, compared.
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It's the most common starting point, but not universal — some planners use a more conservative 28-33x (roughly a 3-3.5% withdrawal rate) for longer retirements or more cautious return assumptions. Treat 25x as a reasonable default to start from, not a guarantee.
It depends on how you plan to fund housing in retirement — if your mortgage will be paid off and you're accounting for property tax, insurance, and maintenance as ongoing expenses, your FI number should reflect that reduced (but nonzero) housing cost, not assume it's free.
No — many people who reach their FI number keep working, just with more freedom to negotiate, switch to lower-stress work, or walk away from a bad situation without financial fear. Financial independence is about having the option, not an obligation to use it.