SuperCalc

FIRE Calculator

Financial Independence, Retire Early (FIRE) is the practice of saving and investing aggressively (40–70% of income) so the corpus throws off enough returns to cover your expenses indefinitely — typically by your 30s or 40s. This calculator runs the full lifetime: aggressive build phase, then a 40–50 year retirement where the math has to actually hold. The hardest question in FIRE isn't 'how soon can I quit?' — it's 'will the money last that long?' This answers both.

Wealth planner

Wealth Projection

Project where your money goes — building it up, drawing it down, or both across your full timeline.

$

Often $0 — just start from your contribution

% / yr
Build phase

Years you contribute. Money grows on contributions plus prior balance.

$
years
% / yr

Common: 5–10% as your income grows. 0 to keep flat.

Spend phase

Retirement years. Corpus keeps earning returns while you withdraw.

$
years
% / yr

Defaults to 3% (inflation).

% / yr

Defaults to 7% (build rate). Lower it (e.g. 6%) for a conservative portfolio.

Inflation (optional)

Grows your spend-phase withdrawal each year, and shows what your future numbers feel like in today's money.

% / yr

0 to ignore

Your $4K/mo lifestyle today, projected forward:
Year 5
$4.6K/mo
Year 10
$5.4K/mo
Y15 (at retirement)
$6.2K/mo
Your projection
Final balance
—
Contributed
—
Total drawn
—
Multiplier
—

How it works

FIRE math is built around the 25× rule: if you can save 25× your annual expenses, you can withdraw 4% per year and have a ~95% chance of the money lasting 30 years (Trinity Study). For a 50-year retirement, the safer multiple is 28–33× and the safer withdrawal rate is 3–3.5%.

The build phase is where FIRE diverges from traditional retirement. By saving 40–60% of post-tax income (vs. the conventional 10–15%), you compress decades of accumulation into years. A 50% savings rate at 7% returns gets you to FIRE in roughly 17 years from a ₹0 start.

The spend phase is harder. A 30-year retirement is well-studied; a 50-year retirement isn't. Sequence-of-returns risk (a bad market in your first 10 years) dominates outcomes. The calculator's 'glide path' input lets you model a more conservative portfolio in retirement — typically 5–6% return assumption vs. 7–8% during the build.

Variants of FIRE worth knowing: Lean FIRE (low-budget, $30k/yr), Fat FIRE (luxury budget, $100k+/yr), Coast FIRE (you've saved enough that it'll grow to your number by retirement age — you can stop saving but must keep working), Barista FIRE (semi-retired with part-time work covering basics).

FAQ

What is FIRE?
FIRE = Financial Independence, Retire Early. It's a movement (popularized by Mr. Money Mustache, ChooseFI, and others) built around saving aggressively in your 20s/30s to retire by 40 or earlier. The math: save 25× your annual expenses, withdraw 4% per year, never run out (probabilistically). Many practitioners aim for 30–33× because traditional retirement studies assume 30-year horizons; FIRE retirements can be 50+.
What's my FIRE number?
Your FIRE number = 25 × your annual expenses (or 33× for safer/longer retirements). If you spend $40k/year, your FIRE number is $1M (conservatively, $1.32M). Use the spend amount in this calculator to see how big your corpus needs to be.
What's a safe withdrawal rate for FIRE?
The original 4% rule was based on 30-year retirements. For FIRE retirements lasting 40–60 years, most studies (Big ERN, etc.) suggest 3–3.5% is safer. The calculator surfaces your withdrawal rate; under 3.5% is the FIRE-safe zone. Above 4% in a long retirement requires hoping the market cooperates.
What savings rate do I need for FIRE?
From zero to FIRE at 7% returns: 50% savings rate gets you there in ~17 years; 60% in ~13 years; 70% in ~8.5 years. Higher savings rate matters more than higher return rate — saving 60% vs. 30% has a bigger effect on time-to-FIRE than 8% vs. 5% returns.
Lean FIRE vs Fat FIRE — what's the difference?
Lean FIRE: minimum-viable retirement, $25-40k/year of expenses, FIRE number ~$1M. Fat FIRE: comfortable retirement, $80-150k/year, FIRE number $2-4M. Most FIRE practitioners are between these, often called 'regular FIRE' (~$50-70k/year, FIRE number $1.25-1.75M).
Should I include Social Security in my FIRE plan?
Most FIRE planners ignore Social Security entirely as a margin of safety — if it's still there at full benefits when you're 65–67, it's gravy. The math has to work without it. This calculator focuses on the corpus you control, which matches that mindset.

Related calculators