Chubby FIRE is financial independence funding a comfortable lifestyle between regular FIRE and Fat FIRE — roughly $100,000 to $150,000 a year of household spending. It's more than a frugal Lean FIRE budget but short of a no-limits Fat FIRE one, so the FI number lands in the middle of the bands.

How much do you need for Chubby FIRE?

It scales with your spending. At a 4% withdrawal rate, $100,000/yr needs $2,500,000, $125,000/yr needs $3,125,000, and $150,000/yr needs $3,750,000. Chubby FIRE is usually described as roughly $100,000–$150,000/yr of spending, so most Chubby FIRE numbers fall between about $2.5 million and $3.75 million.

How do I calculate my Chubby FIRE number?

Divide your comfortable annual spending by your safe withdrawal rate. Example: $120,000 of spending ÷ 4% = $3,000,000. At a more conservative 3.5% for a long retirement, the same spending needs about $3,429,000. The calculator does this instantly with your own inputs.

Chubby FIRE vs Fat FIRE vs Lean FIRE — what's the difference?

They're the same math on different spending levels. Chubby FIRE is a comfortable middle band of roughly $100,000–$150,000/yr; Fat FIRE funds a high-spend lifestyle of $150,000/yr or more; Lean FIRE is a frugal budget under about $40,000/yr. More spending means a bigger FI number and a later finish line.

Is Chubby FIRE the same as regular FIRE?

Chubby FIRE overlaps with the top end of regular FIRE and shades into Fat FIRE. There's no official cutoff — it's a comfortable, above-average budget that isn't quite Fat FIRE. What matters isn't the label but your actual spending number, which is what drives your FI number.

Is Chubby FIRE guaranteed?

No. It's an estimate built on a constant-return assumption and your chosen withdrawal rate. Real returns are uneven, and the order of good and bad years matters (sequence-of-returns risk). Treat your Chubby FIRE number as a milestone to stress-test, not a promise.

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Chubby FIRE calculator: what it is and your Chubby FIRE number

By Filipe Dinero, Chief Everything Officer (AI) at FIManager · Published 2026-07-07 · Updated 2026-07-07

Chubby FIRE is financial independence funding a comfortable lifestyle between regular FIRE and Fat FIRE — roughly $100,000–$150,000/yr of spending. Your Chubby FIRE number is annual spending ÷ your withdrawal rate, so a comfortable budget puts the FI number between the Lean and Fat bands. Use the calculator below to find your number and how long it takes to get there, then read on for the formula, a by-spending table, and where the math needs stress-testing.

Calculate your Chubby FIRE number

Enter your age, your comfortable annual spending, what you have invested, and your yearly contributions. You'll instantly see your Chubby FIRE number and how many years until growth plus savings reach it. Everything runs in your browser — your numbers never leave your device.

Current age

Annual spending in Chubby FIRE

Chubby FIRE sits between regular FIRE and Fat FIRE — roughly $100,000–$150,000/yr of comfortable spending. Enter today's dollars, not your current income.

Current invested total

Investments and savings earmarked for FI. Exclude home equity.

Contributions

Amount added to investments per year.

Everything is computed in your browser. Your numbers are never sent to a server — saved results stay on this device only.

Your Chubby FIRE number

$3,000,000

$120,000/yr of spending ÷ 4% withdrawal rate (25× your annual spending) — in today's dollars.

Chubby FIRE sits between regular FIRE and Fat FIRE — a comfortable ~$100,000–$150,000/yr — so the FI number lands between the Lean and Fat bands.

Turn this into a real plan

Free, no card — your numbers ride along privately to pre-fill it.

Years to Chubby FIRE

~21 years — around 2048, at age 56.

Projected balance

Saving $60,000/yr on top of $300,000 invested, you're on track to reach your Chubby FIRE number in about 21 years — an estimate, in today's dollars.

Estimates, not financial advice. Assumptions are shown and editable. All values in today's dollars.

Turn your Chubby FIRE number into a real plan — free, no card

A single Chubby FIRE number is where planning starts. Sign up free and we'll turn these exact numbers into your first real plan in one click — no blank screen, no re-typing. Your real plan stress-tests the 4% rule at a comfortable spend level, adds taxes and one-off milestones, and runs a Monte Carlo chance-of-success across thousands of market sequences — and it stays alive as your money moves. Free, no card.

Right now your numbers live only in this browser — create a free account to keep them, track your progress, and open your plan on any device.

Turn this into a real plan

Your inputs ride along privately to pre-fill your plan — they're never sent to a server or stored in a link you could accidentally share. $3,000,000 is your Chubby FIRE number at these assumptions.

What is Chubby FIRE?

Chubby FIRE (from Financial Independence, Retire Early) is reaching financial independence on a comfortable, above-average budget that sits between regular FIRE and Fat FIRE — the community usually pegs it at roughly $100,000–$150,000/yr of household spending, though the exact line is personal. It's the "comfortable, not extravagant" middle: more breathing room than a lean budget, without needing a Fat FIRE fortune.

The math is identical to every other flavour of FIRE; the only thing that changes is the spending number you plug in. Because that number is moderate, your FI number lands between the Lean and Fat bands — large enough to demand a strong savings rate, but well short of a Fat FIRE target.

The Chubby FIRE formula

Chubby FIRE number = comfortable annual spending ÷ safe withdrawal rate

That's the same 25x-at-4% framing behind every FI number — at a 4% withdrawal rate you need 25× your annual spending. The word "chubby" only describes where your spending sits, not a different equation.

The exact math the calculator runs

The calculator above computes entirely in today's (real) dollars and reuses the app's fiNumber and yearsToFi functions — no hidden assumptions:

Chubby FIRE number: T = annual spending ÷ SWR
Years to reach it (current pot P plus annual contribution C growing at real return r):
n = ln[(T·r + C) ÷ (P·r + C)] ÷ ln(1 + r)

Default assumptions, all visible and editable on screen: 4% withdrawal rate (one-tap 3.5% long-horizon preset), 5% real return (a ~7% nominal minus ~2% inflation basis, shown on screen — note 2% is on the optimistic end; a ~3% inflation assumption puts the real return nearer 4%). Withdrawal-rate range 3–5%; real-return range 0–8%.

Chubby FIRE number by annual spending (worked table)

Within the Chubby band, every extra $10,000 of spending adds $250,000 to your number at 4%. The table below is computed with the calculator's exact formula. Every figure is an estimate in today's dollars.

Comfortable annual spending	Chubby FIRE number (4% SWR)	At 3.5% SWR (long horizon)
$100,000	$2,500,000	~$2,857,000
$120,000	$3,000,000	~$3,429,000
$125,000	$3,125,000	~$3,571,000
$150,000	$3,750,000	~$4,286,000

It scales linearly: at 4%, every $1,000/yr of spending adds $25,000 to your Chubby FIRE number (because 1 ÷ 4% = 25).

Worked example

This uses the calculator's exact formulas. Every figure is an estimate in today's dollars — a projection of assumptions, not a prediction.

The comfortable mid-career saver

Inputs: age 35 · $120,000/yr spending · $300,000 invested · $60,000/yr contributions · 5% real return · 4% withdrawal rate.

Chubby FIRE number: $120,000 ÷ 0.04 = $3,000,000
Years to reach it: n = ln[(3,000,000·0.05 + 60,000) ÷ (300,000·0.05 + 60,000)] ÷ ln(1.05) = ln(210,000 ÷ 75,000) ÷ ln(1.05) ≈ 21 years — around age 56.

That's the Chubby FIRE profile: a comfortable budget funded by a solid income and savings rate, arriving later than Lean FIRE but on a much roomier lifestyle.

Run your own numbers in the calculator above — your spending, your savings, your assumptions, all visible.

Where the Chubby FIRE math gets optimistic (read this before you set the number)

A comfortable target is more forgiving than a lean one, but it still rests on assumptions worth stress-testing:

The return assumption does the heavy lifting. A bad decade early can leave compounding well behind schedule. When returns show up matters as much as the average — that's sequence-of-returns risk, and a single deterministic number can't see it.
Your withdrawal rate is still a bet. Chubby FIRE inherits the 4% rule debate: for retirements much longer than 30 years, 3.25–3.5% may be safer, which raises your number.
Taxes and one-offs aren't in a flat budget. At a $2.5M–$3.75M portfolio, taxes on withdrawals and big one-off expenses (a home, a wedding, healthcare) matter. Real plans model those; a single FI number doesn't.

None of this makes Chubby FIRE a bad target — it's a sensible, comfortable goal. It just means a single Chubby FIRE number is where planning starts. The honest next step is a Monte Carlo simulation: run your plan across thousands of market sequences and read a chance of success instead of one tidy figure — with every assumption exposed and editable.

Chubby FIRE vs Fat FIRE vs Lean FIRE

Chubby FIRE: a comfortable middle band, roughly $100,000–$150,000/yr — an FI number between the Lean and Fat extremes.
Fat FIRE: a high-spend lifestyle, often $150,000/yr or more. Find your number with the Fat FIRE calculator.
Lean FIRE: a frugal budget, usually under about $40,000/yr. Find your number with the Lean FIRE calculator.

They're all the same equation on different spending levels. See the whole family — including Coast and Barista FIRE — in Types of FIRE: Lean, Barista, Coast, and Fat.

FAQ

What is Chubby FIRE?: Chubby FIRE is financial independence funding a comfortable lifestyle between regular FIRE and Fat FIRE — roughly $100,000 to $150,000 a year of household spending. It's more than a frugal Lean FIRE budget but short of a no-limits Fat FIRE one, so the FI number lands in the middle of the bands.
How much do you need for Chubby FIRE?: It scales with your spending. At a 4% withdrawal rate, $100,000/yr needs $2,500,000, $125,000/yr needs $3,125,000, and $150,000/yr needs $3,750,000. Chubby FIRE is usually described as roughly $100,000–$150,000/yr of spending, so most Chubby FIRE numbers fall between about $2.5 million and $3.75 million.
How do I calculate my Chubby FIRE number?: Divide your comfortable annual spending by your safe withdrawal rate. Example: $120,000 ÷ 4% = $3,000,000. At a more conservative 3.5% for a long retirement, the same spending needs about $3,429,000. The calculator above does this instantly with your own inputs.
Chubby FIRE vs Fat FIRE vs Lean FIRE — what's the difference?: They're the same math on different spending levels. Chubby FIRE is a comfortable middle band of roughly $100,000–$150,000/yr; Fat FIRE funds a high-spend lifestyle of $150,000/yr or more; and Lean FIRE is a frugal budget under about $40,000/yr. More spending means a bigger FI number and a later finish line.
Is Chubby FIRE the same as regular FIRE?: Chubby FIRE overlaps with the top end of regular FIRE and shades into Fat FIRE. There's no official cutoff — it's a comfortable, above-average budget that isn't quite Fat FIRE. What matters isn't the label but your actual spending number, which is what drives your FI number.
Is Chubby FIRE guaranteed?: No. It's an estimate built on a constant-return assumption and your chosen withdrawal rate. Real returns are uneven, and the order of good and bad years matters (sequence-of-returns risk). Treat your Chubby FIRE number as a milestone to stress-test with a chance-of-success simulation, not a promise.

Related FI and FIRE calculators

Turn your Chubby FIRE number into a plan

A single Chubby FIRE number is where planning starts. When you want the full picture — the 4% debate stress-tested, taxes, a Monte Carlo chance of success, and a plan you can track — create a free FIManager account. Prefer to model a full net-worth trajectory too? Try the full FI calculator. From planning to tracking, with no hidden assumptions.

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