FIRE Calculator

Find your FIRE number and the age you can retire early

Finance & BusinessFREEYour data never leaves your browser

100% freeNo signupRuns in your browser

Built by WOWHOW Team · 14+ yrs engineering

FIRE Calculator is a free, browser-based tool that lets you find your fire number and the age you can retire early — with zero signup, zero installation. Your data never leaves your browser. Part of 138+ free developer and business tools at wowhow.cloud, built and maintained by a team with 14+ years of hands-on development experience.

TOOLFIRE Calculator

Current Age30 yrs

Withdrawal Rate4%

4% is the classic rule

Annual Spending in Retirement$50,000

Current Invested Assets$100,000

Annual Investment / Savings$30,000

Expected Return7%

Inflation3%

Real return after inflation: 3.88%. All figures are in today's dollars.

Your FIRE Number

$1,250,000

$1.25M — 4% of this covers $50,000/yr

FIRE Age

Age 53

Years to FIRE

23 yrs

Progress to FIRE8.0%

○ Coast FIRE: $329,443 — reach this and your portfolio alone grows to your FIRE number by age 65, even if you stop adding money.

Lean FIRE

Frugal · 70% spend

$875K

FIRE

Your target

$1.25M

Fat FIRE

Comfortable · 2x spend

$2.50M

Portfolio Growth

Age 30FIRE line at 100%Age 53

About FIRE Calculator

FIRE — Financial Independence, Retire Early — turns retirement from an age into a number: the portfolio size at which investment returns cover your living costs forever. This calculator finds that number from your spending and withdrawal rate, then projects your real, inflation-adjusted savings forward to the exact year you cross the line, including the Coast, Lean, and Fat FIRE milestones along the way.

How It Works

Your FIRE number is annual spending divided by your safe withdrawal rate (4% by default, i.e. 25× spending). The calculator then projects your portfolio forward year by year using a real rate of return — your expected return minus inflation — so every figure stays in today’s dollars and the target never moves.

Each year the balance grows by the real return and gains your annual contribution, until it reaches the FIRE number; that crossing point is your FIRE age. The tool also computes Coast FIRE — the amount that would compound to your target by age 65 with no further saving — and flags whether you are already there.

Lean FIRE (70% of spending) and Fat FIRE (double spending) give you the full range, and a sampled growth chart shows the trajectory. All computation is client-side.

Who Is This For

A 30-year-old software engineer with $100k invested and $30k/year savings finding they hit FIRE at 48 on the 4% rule.

Someone testing how dropping their withdrawal rate from 4% to 3.5% pushes their FIRE number and timeline.

A high earner checking whether they have already reached Coast FIRE and can ease off aggressive saving.

A frugal saver comparing a Lean FIRE target against a Fat FIRE lifestyle to decide how long to keep working.

Scope note: Projections assume constant returns, inflation, spending, and contributions — real markets are volatile and sequence-of-returns risk in early retirement can break a naive 4% withdrawal. The model ignores taxes, healthcare cost growth, Social Security, and one-off expenses. Use it to frame a target and timeline, not as a guarantee, and stress-test with a lower withdrawal rate before quitting your job.

Disclaimer: This calculator is for informational and educational purposes only and does not constitute financial, tax, or legal advice. Results are estimates based on publicly available tax slabs and formulas. Consult a qualified Chartered Accountant, tax professional, or financial advisor for guidance specific to your situation. Built and maintained by the WOWHOW Team with 14+ years of software development experience.

How to Use

Enter the annual spending you expect in retirement — your FIRE number is built from this

Add your current invested assets and how much you invest each year

Set your expected return, inflation, and safe withdrawal rate (4% is the classic rule)

Read your FIRE number, the age you hit it, and whether you have already reached Coast FIRE

Frequently Asked Questions

Your FIRE number is your expected annual retirement spending divided by your safe withdrawal rate. At the classic 4% rule, that is spending × 25 — so $50,000/year needs a $1,250,000 portfolio. Lower the withdrawal rate for a more conservative target and the number rises.

The 4% rule comes from the Trinity Study: historically, withdrawing 4% of a stock/bond portfolio in year one and adjusting for inflation each year survived 30+ years in almost all scenarios. It is a planning rule of thumb, not a guarantee — sequence-of-returns risk and longer retirements may call for 3–3.5%.

Coast FIRE is the amount you need invested today so that, with zero further contributions, compound growth alone reaches your full FIRE number by traditional retirement age (65 here). Once you hit Coast FIRE you can stop investing and still retire on time — you only need to cover current expenses.

Yes. The calculator projects in today’s dollars by using a real rate of return — your expected return minus inflation. That keeps your FIRE number constant and comparable to your current spending, so the timeline reflects real purchasing power.

No. Every figure stays in your browser and is never sent to a server. Close the tab and nothing is stored.