FIRE Calculator
Find your FIRE number, see how many years stand between you and financial independence, and watch how your savings rate — not your investment return — does most of the work. Built on the 4% rule, in today’s dollars.
If you spend $50,000/year and use a 4% withdrawal rate, your FIRE number is $1.25 million (25× annual expenses). Starting at 30 with $100,000 invested and saving $30,000/year at a 7% real return, you’d reach financial independence in about 18 years — at age 48. Raise your savings rate and that timeline collapses fast; it matters far more than chasing returns.
FIRE Calculator
Your numbers
Educational estimate in today’s dollars. Assumes a constant real return and level contributions — real markets vary. Excludes taxes on withdrawals, healthcare costs, and sequence-of-returns risk. Not financial advice.
Your path to FI
33% savings rateYour FIRE number is simply your annual spending divided by your withdrawal rate. At 4%, that’s 25× your yearly costs.
FIRE math has one dominant variable: the gap between what you earn and what you spend. Cutting spending does double duty — it raises your savings rate and lowers the FIRE number you’re aiming at.
What this calculator does
FIRE — Financial Independence, Retire Early — is the idea that once your invested assets can safely fund your annual spending forever, paid work becomes optional. This calculator answers the two questions that matter: how big does the portfolio need to be, and how long until you get there at your current savings pace.
Everything is computed in today’s dollars using a real (after-inflation) return, which is how the FIRE community thinks about it. That keeps the numbers intuitive: a $1.25M target means $1.25M of today’s purchasing power.
Who should use it
Anyone curious about the trade-off between spending now and freedom later — whether you want to retire at 40, build a work-optional cushion, or simply see what a higher savings rate would buy you in years of your life.
This is a planning model, not a promise. It assumes steady real returns and level contributions, and it excludes taxes on withdrawals, US healthcare costs before Medicare at 65, and sequence-of-returns risk. Treat the FI date as a target to steer toward with a margin of safety.
How FIRE math works
The foundation is the 4% rule, from research showing that a portfolio withdrawing 4% in year one, adjusted for inflation thereafter, historically survived 30 years in the large majority of cases. Invert it and you get the 25× rule: you need roughly 25 times your annual expenses invested.
Because early retirement can last 40–50 years rather than 30, many in the FIRE community use a more conservative 3% to 3.5% withdrawal rate — which raises the target to roughly 29×–33× expenses. That’s the trade-off this calculator lets you test directly.
The formula
Why the savings rate rules everything
The single most counterintuitive result in FIRE math: your savings rate determines your timeline far more than your investment return does. That’s because saving more does two things simultaneously — it accelerates the portfolio’s growth and shrinks the target, since you’re living on less.
Roughly speaking, at a 10% savings rate financial independence takes about 50 working years; at 25% it’s roughly 32 years; at 50% it drops to around 17; and at 65% you’re looking at little more than a decade. Chasing an extra percentage point of return might shave a year or two — raising your savings rate by 15 points can cut a decade or more.
Cutting $10,000 from your annual spending doesn’t just free up $10,000 to invest — it also lowers your FIRE number by $250,000 at a 4% withdrawal rate. That’s why frugality is the engine of FIRE, not high income alone.
Types of FIRE
| Flavor | What it means |
|---|---|
| Lean FIRE | Retire on a deliberately minimal budget — often under $40k/year — so the target is smaller and arrives sooner. |
| Fat FIRE | Retire with an abundant lifestyle, typically $100k+/year of spending, requiring a much larger portfolio. |
| Coast FIRE | You’ve invested enough that compounding alone will fund a traditional retirement — so you can stop saving and simply cover current expenses. |
| Barista FIRE | Partial independence: a portfolio covering most costs, topped up with part-time work (often for health insurance). |
Worked examples
Example 1 — Standard path (age 30)
$50k spending, $100k invested, $30k/yr saved, 7% real, 4% SWR.
FIRE number = $50,000 ÷ 0.04 = $1,250,000. With $100k already working and $30k added yearly, the portfolio crosses the target in about 18 years — at age 48. A savings rate of roughly 33% of take-home income is doing the heavy lifting.
Example 2 — Lean FIRE, high savings rate
$40k spending, $50k invested, $40k/yr saved, 7% real, 4% SWR.
Lower spending cuts the target to $1,000,000, and the aggressive $40k/year contribution reaches it in just 14 years — at age 44, despite starting with half the savings of Example 1. Spending less and saving more beats starting with more.
Example 3 — The conservative 3.5% rule
Same as Example 1 but with a 3.5% withdrawal rate.
Dropping to 3.5% raises the target to $1,428,571 (about 29× spending) and pushes FI out to 19 years — age 49. One extra year of work buys a meaningfully larger safety cushion for a 40-year retirement. For most early retirees, that’s a trade worth making.
The risks nobody mentions
Sequence-of-returns risk. A severe market drop in your first few retirement years, while you’re withdrawing, can permanently damage a portfolio — even if average returns later recover. Keeping one to two years of spending in cash, and staying flexible on withdrawals in bad years, is the standard defense.
Healthcare before 65. This is the great American FIRE problem. Medicare doesn’t start until 65, so an early retiree must self-fund coverage — typically through an ACA marketplace plan, where premiums depend on income (and managed withdrawals can qualify you for subsidies). Budget for it explicitly; it’s often the largest line item people forget.
The 4% rule isn’t a guarantee. It came from 30-year historical windows. A 45-year retirement is a different problem, which is why lower withdrawal rates and part-time income are so common in practice.
Accessing money before 59½
Most retirement money sits in accounts with early-withdrawal penalties, so early retirees use specific strategies to bridge the gap:
- Taxable brokerage account. No age restrictions — the simplest bridge, and why many FIRE savers deliberately invest beyond tax-advantaged accounts.
- Roth conversion ladder. Convert traditional IRA money to Roth in low-income years; each converted amount can be withdrawn penalty-free five years later. Requires planning ahead by five years.
- Rule 72(t) / SEPP. Substantially equal periodic payments let you tap an IRA early without penalty, but the schedule is rigid and hard to unwind.
- Roth contributions. Your own Roth IRA contributions (not earnings) can be withdrawn anytime, tax- and penalty-free.
Common mistakes
- Underestimating spending. The FIRE number is entirely driven by it — a $5,000/year miss means being $125,000 short at a 4% rate.
- Using nominal returns as real returns. If you enter 10% while inflation runs 3%, you’re overstating growth. Use a real return.
- Forgetting healthcare. Pre-Medicare coverage can run five figures a year for a family. Include it in your spending number.
- Ignoring taxes on withdrawals. Traditional 401(k)/IRA money is taxed as income when you draw it; your gross need is higher than your net spending.
- Applying the 4% rule to a 50-year retirement. It was validated over 30 years. Longer horizons warrant 3–3.5%.
- Treating FI as all-or-nothing. Partial independence — Coast or Barista FIRE — delivers most of the freedom far sooner.
Frequently asked questions
What is a FIRE number?
What is the 4% rule?
Should I use 4% or 3.5%?
How much does my savings rate matter?
What return should I assume?
What about health insurance before 65?
How do I access retirement accounts before 59½?
What is Coast FIRE?
Does this account for taxes?
Is retiring early actually realistic?
Is this financial advice?
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