finance calculator

FIRE Calculator

Estimate your financial independence number and early retirement timeline based on savings rate and expected investment returns.

Formula Verified by Dr. Elizabeth Vance, PhD

Quick actions: Save inputs, view saved runs, print, share, or export results

Saved Runs

Inputs

Current age

Current savings$

Annual expenses$

Monthly savings$

Annual return%

Withdrawal rate%

Results

FIRE number

$1,250,000

Estimated FIRE age48.0

Years to FIRE18.0 years

Amount still needed$1,200,000

Savings rate37.50%

Tip

Return when expenses, savings, returns, or withdrawal-rate assumptions change.

Formula

FIRE number formula

FIRE number = annual expenses / withdrawal rate

The FIRE target estimates the portfolio size needed to support annual expenses at the chosen withdrawal rate.

Step by step

How the calculation works

1Enter current savings, annual expenses, and monthly savings.
2The calculator estimates the target portfolio from the withdrawal rate.
3It projects contributions and growth until the target is reached.

Example

FIRE example

With $50,000 saved, $2,500 saved monthly, $50,000 annual expenses, and a 4% withdrawal rate, the target FIRE number is $1.25M.

Related guides

Learn more about this calculation

Guide

FIRE Planning Guide: FIRE Number, Timeline, Withdrawal Rate, and Reality Checks

Learn how FIRE planning translates spending into a target portfolio, how the DTC calculator estimates your timeline, and where early-retirement math usually breaks.

Guide

Retirement Savings Timeline: Plan by Stage and Age

Build a retirement savings timeline, project contributions, test return assumptions, and review current U.S. account limits and planning gaps.

How to understand and use this calculator

What This Calculator Does

This calculator estimates the portfolio size needed to support your annual expenses indefinitely at a chosen withdrawal rate — your FIRE number — then projects your current savings and ongoing monthly contributions forward, month by month, until that target is reached.

It returns your FIRE number, the amount still needed, months and years to FIRE, your projected FIRE age, and the savings rate that trajectory implies — turning an abstract "financial independence" goal into a concrete, testable timeline.

How to Use This Calculator

Enter your current age, current investment savings, annual expenses (what you actually spend to live, not your income), monthly savings contribution, expected annual investment return, and target withdrawal rate.

The calculator computes your FIRE number from expenses and withdrawal rate, then simulates monthly compounding growth plus your monthly contribution until the balance reaches that number, returning the exact month and age it happens.

The Formula Behind the Numbers

FIRE Number = (Annual Expenses)/(Withdrawal Rate)

Each month, the simulation applies:

Balance_(t+1) = Balance_t × (1 + (Annual Return)/12) + Monthly Savings

repeating until Balance ≥ FIRE Number, at which point that month count becomes your years and age to FIRE.

Worked Example: $50,000 Expenses, 4% Withdrawal Rate

Age 30, $50,000 already saved, $50,000 in annual expenses, $2,500 saved monthly, a 7% expected annual return, and a 4% withdrawal rate.

FIRE number: $50,000 ÷ 0.04 = $1,250,000.

Amount still needed: $1,250,000 − $50,000 = $1,200,000.

Simulating monthly growth and contributions, the balance crosses $1,250,000 at month 216 — exactly 18 years.

FIRE age: 30 + 18 = 48.

Implied savings rate: roughly 37.5% of the combined savings-plus-expenses total ($2,500 × 12 = $30,000 saved annually against $50,000 in expenses).

So this household reaches financial independence at 48 — nearly two decades before a traditional retirement age — purely from a 37.5% savings rate and steady 7% returns compounding monthly over that period.

Why the Withdrawal Rate Drives Everything

The withdrawal rate you choose has an outsized effect on your FIRE number because it's a direct divisor: dropping from 4% to 3.5% raises the same $50,000 in expenses from a $1,250,000 target to about $1,428,571 — a $178,571 increase in the number you need to hit, and correspondingly more years to get there. The widely cited 4% figure comes from the Trinity Study, which found a 4% initial withdrawal rate (adjusted annually for inflation) succeeded over 95% of rolling 30-year historical periods — but it was modeled on a traditional ~30-year retirement horizon, and many FIRE planners choose a more conservative 3–3.5% specifically because an early retirement can mean a 40–50+ year withdrawal period, which the original study didn't directly test.

What This Simplified Model Doesn't Capture

This projection assumes a constant annual return applied smoothly every month, which real markets never actually deliver — a sequence of poor returns early in the accumulation phase (or worse, early in retirement) can meaningfully change real-world outcomes even with an identical average return over time. It also doesn't model taxes, inflation-adjusted rising expenses, Social Security or pension income, or part-time "Barista FIRE" income that many early retirees use to reduce how much their portfolio needs to cover. Treat the FIRE age this calculator produces as a directional planning estimate — useful for tracking progress and testing assumptions, not a guarantee — and revisit it periodically as your real savings rate and market returns unfold.

LeanFIRE, FatFIRE, and CoastFIRE: Same Formula, Different Targets

The FIRE number formula stays identical across every FIRE variant — only the annual expenses input changes. A LeanFIRE target built around $35,000 in annual expenses at a 4% withdrawal rate needs $875,000. A standard FIRE target around $50,000 in expenses needs $1,250,000, as in the worked example above. A FatFIRE target built around $120,000 in expenses needs $3,000,000 — more than triple the standard target, purely because the desired lifestyle costs more to sustain indefinitely.

CoastFIRE works differently: instead of asking "how much do I need saved by retirement," it asks "how much do I need saved right now so that compounding alone — with zero further contributions — carries me to my full FIRE number by a target age." Reaching CoastFIRE means you could stop saving entirely and still hit your number through growth alone, which is why many people use it as an earlier, motivating milestone on the way to full financial independence.

Related Calculators

Once you have a FIRE number, stress-test it against real market volatility with the Monte Carlo retirement simulator, or compare it against a traditional retirement-age projection with the retirement calculator.

Track your progress toward that FIRE number with the net worth calculator — your current net worth, tracked over time, is the real-world signal of whether you're on pace.

Related concepts

FIRE number

The portfolio target estimated from annual expenses and withdrawal rate.

Withdrawal rate

The annual percentage of portfolio value used for living expenses in retirement.

Savings rate

The share of income directed toward financial independence rather than spending.

Sequence-of-returns risk

The danger that poor market returns early in retirement accelerate portfolio depletion.

Trinity Study

The historical research behind the commonly cited 4% withdrawal rate rule.

CoastFIRE

Having saved enough early that a portfolio will compound to your target without further contributions.

Frequently Asked Questions

What withdrawal rate should I use?+

Many people start with 4% as a rough planning rule, but lower rates are more conservative.

Does FIRE mean I must stop working completely?+

No. Some people use FIRE planning for flexibility, part-time work, or career changes.

Does this include inflation?+

No. Use conservative return and expense assumptions if you want a rough inflation-aware view.

What is the difference between LeanFIRE, FatFIRE, and CoastFIRE?+

LeanFIRE is retiring early on a minimalist budget (e.g., under $40,000/year). FatFIRE is retiring early with an abundant lifestyle (e.g., over $100,000/year). CoastFIRE is saving enough early in life so that your portfolio will compound to your target retirement number without further contributions, allowing you to work only to cover current living expenses.

What is sequence-of-returns risk?+

Sequence-of-returns risk is the danger that market downturns occur in the early years of your retirement. Withdrawing money from a shrinking portfolio accelerates its depletion, significantly increasing the risk of running out of money.

How do I access my retirement accounts before age 59.5 without penalty?+

Common strategies include building a Roth IRA conversion ladder (converting Traditional funds to Roth and withdrawing contributions after 5 years), utilizing SEPP (Substantially Equal Periodic Payments) under IRS Rule 72(t), or using taxable brokerage accounts as a bridge.

What is the Trinity Study and why is it important?+

The Trinity Study is a landmark financial paper that analyzed portfolio success rates over historical retirement periods. It established that a 4% initial withdrawal rate (adjusted annually for inflation) had a 95%+ historical probability of lasting 30 years.

How do early retirees handle healthcare in the United States?+

Early retirees typically buy insurance through the Affordable Care Act (ACA) exchange, using their low taxable income to qualify for premium tax subsidies. Other options include health share ministries, working part-time for benefits (BaristaFIRE), or moving abroad.

Should I change my asset allocation as I near my FIRE date?+

Yes. Many early retirees shift toward a more conservative allocation (adding bonds or cash) to mitigate sequence-of-returns risk. Some use a "bond tent" structure, starting retirement with more bonds and gradually shifting back to equities over time.

What is a cash cushion or bond tent?+

A cash cushion is 1-3 years of living expenses kept in liquid accounts. A bond tent is a temporary increase in bond allocation around your retirement date. Both allow you to draw down cash or bonds during market crashes, avoiding selling stocks at a loss.

What is a dynamic withdrawal strategy?+

A dynamic withdrawal strategy adjusts your annual spending based on portfolio performance. If the stock market drops, you reduce your spending; if it gains, you spend more. This flexibility significantly increases portfolio longevity.

What is geographical arbitrage?+

Geographical arbitrage is earning income in a high-cost area or currency (like US dollars) and retiring in a low-cost region or country. This dramatically lowers the annual expenses needed to retire, reducing your target FIRE number.

How much does lowering my withdrawal rate change my FIRE number?+

A lot — it's a direct divisor. Dropping from 4% to 3.5% on $50,000 in expenses raises the target from $1,250,000 to about $1,428,571, since the same expenses now need a larger portfolio to support at the more conservative rate.

Does increasing my savings rate matter more than chasing higher returns?+

For most people, yes, especially early on — savings rate is fully within your control and has an outsized effect on timeline, while investment returns are uncertain and outside your control. Many FIRE planners prioritize raising savings rate over trying to beat market returns.

What's the difference between FIRE and CoastFIRE numbers?+

The FIRE number is the full portfolio needed to cover expenses indefinitely at your withdrawal rate. The CoastFIRE number is smaller — it's how much you need saved right now so that growth alone, with no further contributions, reaches your full FIRE number by a target age.

How accurate is a 7% annual return assumption?+

It is a commonly used long-run average for diversified stock portfolios after accounting for typical historical performance, but actual year-to-year returns vary widely and are never smooth — treat it as a planning average, not a guaranteed rate.

What is BaristaFIRE?+

BaristaFIRE describes leaving a full-time career once your portfolio can cover most expenses, then working a lower-stress part-time job (often for supplemental income or health benefits) to cover the remaining gap instead of relying on the portfolio alone.

How to understand and use this calculator

What This Calculator Does

How to Use This Calculator

The Formula Behind the Numbers

FIRE Number = (Annual Expenses)/(Withdrawal Rate)

Each month, the simulation applies:

Balance_(t+1) = Balance_t × (1 + (Annual Return)/12) + Monthly Savings

repeating until Balance ≥ FIRE Number, at which point that month count becomes your years and age to FIRE.

Worked Example: $50,000 Expenses, 4% Withdrawal Rate

Age 30, $50,000 already saved, $50,000 in annual expenses, $2,500 saved monthly, a 7% expected annual return, and a 4% withdrawal rate.

FIRE number: $50,000 ÷ 0.04 = $1,250,000.

Amount still needed: $1,250,000 − $50,000 = $1,200,000.

Simulating monthly growth and contributions, the balance crosses $1,250,000 at month 216 — exactly 18 years.

FIRE age: 30 + 18 = 48.

Implied savings rate: roughly 37.5% of the combined savings-plus-expenses total ($2,500 × 12 = $30,000 saved annually against $50,000 in expenses).

Why the Withdrawal Rate Drives Everything

What This Simplified Model Doesn't Capture

LeanFIRE, FatFIRE, and CoastFIRE: Same Formula, Different Targets

Related Calculators

Track your progress toward that FIRE number with the net worth calculator — your current net worth, tracked over time, is the real-world signal of whether you're on pace.

Related concepts

FIRE number

The portfolio target estimated from annual expenses and withdrawal rate.

Withdrawal rate

The annual percentage of portfolio value used for living expenses in retirement.

Savings rate

The share of income directed toward financial independence rather than spending.

Sequence-of-returns risk

The danger that poor market returns early in retirement accelerate portfolio depletion.

Trinity Study

The historical research behind the commonly cited 4% withdrawal rate rule.

CoastFIRE

Having saved enough early that a portfolio will compound to your target without further contributions.

Frequently Asked Questions

What withdrawal rate should I use?+

Many people start with 4% as a rough planning rule, but lower rates are more conservative.

Does FIRE mean I must stop working completely?+

No. Some people use FIRE planning for flexibility, part-time work, or career changes.

Does this include inflation?+

No. Use conservative return and expense assumptions if you want a rough inflation-aware view.

What is the difference between LeanFIRE, FatFIRE, and CoastFIRE?+

What is sequence-of-returns risk?+

How do I access my retirement accounts before age 59.5 without penalty?+

What is the Trinity Study and why is it important?+

How do early retirees handle healthcare in the United States?+

Should I change my asset allocation as I near my FIRE date?+

What is a cash cushion or bond tent?+

What is a dynamic withdrawal strategy?+

What is geographical arbitrage?+

How much does lowering my withdrawal rate change my FIRE number?+

Does increasing my savings rate matter more than chasing higher returns?+

What's the difference between FIRE and CoastFIRE numbers?+

How accurate is a 7% annual return assumption?+

What is BaristaFIRE?+

FIRE Calculator

Inputs

Results

FIRE number formula

How the calculation works

FIRE example

Learn more about this calculation

FIRE Planning Guide: FIRE Number, Timeline, Withdrawal Rate, and Reality Checks

Retirement Savings Timeline: Plan by Stage and Age

FIRE Calculator

Inputs

Results

Key output metrics

Current savings vs remaining FIRE gap

Path to FIRE timeline

How to understand and use this calculator

What This Calculator Does

How to Use This Calculator

The Formula Behind the Numbers

Worked Example: $50,000 Expenses, 4% Withdrawal Rate

Why the Withdrawal Rate Drives Everything

What This Simplified Model Doesn't Capture

LeanFIRE, FatFIRE, and CoastFIRE: Same Formula, Different Targets

Related Calculators

Related concepts

Frequently Asked Questions

FIRE number formula

How the calculation works

FIRE example

Learn more about this calculation

FIRE Planning Guide: FIRE Number, Timeline, Withdrawal Rate, and Reality Checks

Retirement Savings Timeline: Plan by Stage and Age

Key output metrics

Current savings vs remaining FIRE gap

Path to FIRE timeline

How to understand and use this calculator

What This Calculator Does

How to Use This Calculator

The Formula Behind the Numbers

Worked Example: $50,000 Expenses, 4% Withdrawal Rate

Why the Withdrawal Rate Drives Everything

What This Simplified Model Doesn't Capture

LeanFIRE, FatFIRE, and CoastFIRE: Same Formula, Different Targets

Related Calculators

Related concepts

Frequently Asked Questions