FIRE Number Calculator

Use this calculator to find your FIRE Number: the portfolio size at which your investments can sustainably fund your retirement indefinitely. Enter your annual expenses, current savings, and monthly contributions to get your personalized FIRE date across five retirement strategies.

What Is a FIRE Number?

Your FIRE Number is the total investment portfolio value you need to retire and never work again. The most common formula is Annual Expenses x 25, which comes directly from the 4% Rule: if your portfolio can safely return 4% per year, you need 25 times your annual spending to cover expenses forever.

If you spend $50,000 per year, your FIRE Number is $1,250,000. Once your portfolio hits that number, work becomes optional.

The 5 Types of FIRE

Lean FIRE

Lean FIRE is for people committed to a frugal, minimalist lifestyle. It uses a 5% withdrawal rate and a 20x multiplier, so a $30,000/year spender needs a $600,000 portfolio. It’s the fastest path to financial independence, but requires strict spending discipline once you stop working.

Regular FIRE

Regular FIRE is the classic approach: maintain your current lifestyle using the 4% rule. A household spending $60,000 per year needs $1.5 million. It’s the most widely researched and backtested retirement strategy, with a strong historical success rate across 30-year retirements.

Fat FIRE

Fat FIRE targets a higher standard of living in retirement. It uses a 3% withdrawal rate and a 33x multiplier, so $80,000 in annual spending requires a $2.64 million portfolio. The larger cushion provides more safety against sequence-of-returns risk and allows for lifestyle flexibility.

Coast FIRE

Coast FIRE is a two-phase strategy. First, you invest enough that compound growth alone will reach your full FIRE Number by a target retirement age, typically 65, with no further contributions needed. Then you “coast”: cover living expenses with part-time or lower-stress work without adding to your portfolio.

This calculator shows your Coast FIRE Number, the lump sum needed today to coast to retirement hands-free.

Barista FIRE

Barista FIRE is semi-retirement. You reduce your portfolio size by earning a modest part-time income, like a coffee shop job or freelance work, that covers part of your expenses. Your portfolio only needs to cover the gap. This lets you leave your primary career years earlier than full FIRE, while keeping some structure and social connection.

How to Use This Calculator

1. Enter your annual expenses: what you actually spend, or what you plan to spend in retirement
2. Enter your current portfolio: everything invested: 401(k), IRA, brokerage accounts, and savings
3. Set your monthly savings: your regular monthly investment contribution
4. Adjust the return rate: 7% is the real (inflation-adjusted) S&P 500 historical average
5. Pick a FIRE variant: select the tab that matches your retirement lifestyle goal
6. Read your results: your FIRE Number, years to retire, FIRE Age, and projected monthly income all update instantly

The Years to FIRE field shows how long until your portfolio reaches the target. FIRE Age adds that to your current age. Monthly Income is the spending power your portfolio generates at the chosen withdrawal rate. Use Share Results to save a link with your exact inputs.

The 4% Rule: What It Means and Its Limits

The 4% rule comes from the 1998 Trinity Study, a landmark analysis by three Trinity University professors who backtested various stock/bond portfolios across historical 30-year periods. They found that a 4% annual withdrawal, adjusted for inflation each year, had a 95%+ historical success rate, meaning the portfolio didn’t run out of money across nearly every historical market scenario.

The rule has real limitations. It was designed for a 30-year retirement, making it potentially too optimistic for early retirees expecting 40 to 50 year retirements. For those cases, a 3.5% withdrawal rate is often recommended as a safer floor. The study also doesn’t account for taxes, healthcare costs, or sequence-of-returns risk when markets drop early in retirement.

Most financial planners treat 4% as a starting estimate, not a guarantee. Dynamic spending strategies, where you spend less in down markets, can meaningfully improve long-term outcomes.

How to Reach Your FIRE Number Faster

There are three levers, in order of impact: increase your savings rate, reduce expenses, and increase income. The savings rate is the most powerful because it simultaneously reduces your FIRE Number (lower expenses mean a smaller target) and speeds up accumulation.

Here’s what that looks like with real numbers. A 30-year-old earning $80,000 with $50,000 in expenses saves $12,000 per year (a 20% savings rate) and needs a $1.25 million portfolio, reaching it in about 26 years. At a 40% savings rate, saving $32,000 per year and spending $48,000, the FIRE Number drops to $1.2 million and the timeline shrinks to roughly 17 years. Nine years saved by raising the savings rate by 20 percentage points.

Frequently Asked Questions

How much do I need to retire at 40?

To retire at 40 using the 4% rule, you need 25 times your annual expenses. If you spend $50,000 per year, your FIRE number is $1.25 million. Because a retirement at 40 could last 50 or more years, many early retirees target a 3.5% withdrawal rate instead, which means 28 times expenses, for extra safety. A high savings rate in your 20s and 30s, combined with low-cost index investing, is the most reliable path.

How much do I need to retire at 35?

Retiring at 35 means funding potentially 55 to 60 years of retirement. Most financial advisors recommend a 3 to 3.5% withdrawal rate rather than the standard 4%. Using the 3.5% rate, you’d need approximately 28 times your annual expenses: $1.4 million for a $50,000 per year lifestyle. Starting to invest aggressively in your early 20s and keeping expenses low are the critical inputs for this timeline.

What is a good savings rate for FIRE?

A 50% savings rate is often cited as the benchmark for FIRE, as it leads to financial independence in roughly 17 years from a zero starting point. A 25% savings rate takes about 32 years; a 75% rate gets you there in about 7 years. The higher your savings rate, the faster you reach FIRE, because you’re building the portfolio faster and reducing your target at the same time.

Is the 4% rule still valid in 2025 and 2026?

The 4% rule remains a useful starting framework, but many researchers now suggest 3.3 to 3.5% as a more conservative safe withdrawal rate given current market valuations. For retirements lasting 40 or more years, typical for early retirees, building in a safety margin through flexible spending, part-time income, or a lower initial withdrawal rate is increasingly recommended.

What is the difference between Lean FIRE and Fat FIRE?

Lean FIRE targets a minimal lifestyle with a 5% withdrawal rate and a 20x spending multiplier. Fat FIRE targets a comfortable or luxurious lifestyle with a 3% withdrawal rate and a 33x multiplier. A $40,000 per year lifestyle requires $800,000 for Lean FIRE; a $90,000 per year lifestyle requires $2.97 million for Fat FIRE. The right choice depends on your desired retirement lifestyle and how much risk you’re comfortable carrying.

What is Coast FIRE?

Coast FIRE is a milestone where you’ve invested enough that compound growth alone, with no additional contributions, will grow your portfolio to your full FIRE Number by a standard retirement age. Once you hit your Coast FIRE Number, you can take lower-paying or more fulfilling work to cover current expenses without saving another dollar. This calculator shows your Coast FIRE Number under the Coast FIRE tab.

What is Barista FIRE?

Barista FIRE is a semi-retirement strategy where you leave your primary career early but work a part-time job to cover part of your living expenses. Your portfolio only needs to cover the remainder. This lets you achieve early semi-retirement with a smaller portfolio than full FIRE requires, while keeping income, structure, and social connection in your daily life.

Does this calculator account for inflation?

All return rate inputs in this calculator are intended as real, inflation-adjusted returns. The S&P 500 has returned approximately 10% nominal and 7% real (after roughly 3% average inflation) historically. By entering 7% as your expected return, your results are already expressed in current purchasing power. Enter your expenses in current dollars and the calculator handles the rest.

Can I use this calculator outside the US?

Yes. Switch to EUR, GBP, INR, AUD, or PHP using the currency selector. The underlying math, the 4% rule, compound growth, and withdrawal rates, is universal. The 4% rule originates from US market data, so international investors may want to use a slightly more conservative rate of 3 to 3.5% to account for local market conditions and currency risk.

About This Tool

Most FIRE calculators give you one number: your 25x target. This one shows all five FIRE variants side by side, calculates your Coast FIRE milestone, and projects your portfolio growth month by month on a chart. It works in multiple currencies and generates a shareable link with your exact inputs. Free to use, no account required, and the formulas are open and visible. Not financial advice.