Select Your FIRE Goal
Your Numbers
How to Use This Calculator
- Select your FIRE type — Lean (frugal lifestyle), Regular (comfortable spending), or Fat (generous, no-compromise retirement).
- Enter your projected annual expenses in retirement. Be honest: underestimating here is the most common planning mistake.
- Enter your current total savings and investments — 401k, IRA, brokerage accounts, and any other invested assets.
- Add your current monthly contribution across all accounts.
- Enter your current age so the calculator can tell you your projected FIRE age.
- Adjust the withdrawal rate (the 4% rule is the default) and your expected annual return.
- Click Calculate to see your FIRE number, years to retirement, progress bar, monthly savings targets, and a Lean/Regular/Fat comparison.
How the FIRE Number Works
The Core Formula
Your FIRE number is the total portfolio value you need to sustain your lifestyle indefinitely without working. The calculation is straightforward: divide your expected annual retirement expenses by your planned withdrawal rate. At a 4% withdrawal rate, a $60,000 annual spending target requires a $1.5 million portfolio. At 3.5%, you’d need roughly $1.71 million. The withdrawal rate you choose is one of the biggest levers in the entire equation — lowering it by even half a percent dramatically increases the portfolio required.
The 4% Rule — and Its Limits
The 4% rule originated from the Trinity Study, a 1998 research paper that analyzed historical market data going back to 1926. It found that a diversified portfolio of stocks and bonds could sustain a 4% annual withdrawal for at least 30 years in 95% of historical scenarios. This made 4% a widely accepted starting point for retirement planning. However, the original study assumed a 30-year retirement — if you’re pursuing early retirement at 40, your money may need to last 50 or 60 years. Many FIRE practitioners use a more conservative 3% or 3.5% rate to account for longer time horizons, sequence-of-returns risk, and uncertainty about future market conditions.
Lean, Regular, and Fat FIRE
The FIRE movement has evolved to recognize that “retirement” looks different for everyone. This calculator uses three tiers based on your baseline expense estimate: Lean FIRE targets 75% of your input expenses — a frugal, minimalist lifestyle with minimal discretionary spending. Regular FIRE uses your expenses as entered, representing a comfortable but not extravagant retirement. Fat FIRE scales to 150% of your base expenses, allowing for travel, dining out, significant discretionary spending, and financial flexibility. The right tier depends entirely on what you want your retired life to look like.
How Years to FIRE Is Calculated
The calculator uses the future value formula for a growing portfolio with regular contributions. Your current savings compounds at the expected annual return, and each monthly contribution is added and compounds forward. The calculator solves numerically for the number of months required to reach your FIRE number, then converts to years and adds your current age to produce a projected FIRE age. If you enter no monthly contributions, the calculation relies entirely on compounding of existing savings — which works, but typically produces a much longer timeline.
Monthly Savings Needed
In addition to your current trajectory, the calculator shows how much you’d need to save each month to hit your FIRE number in 10, 15, or 20 years. This is useful for reverse-engineering a savings plan: if you want to retire in 15 years and your current contributions fall short of that target, you know exactly by how much you’d need to increase them. This figure accounts for the growth of your existing portfolio, so it represents the additional monthly savings required — not the total from scratch.
FIRE Number Reference Table
| Annual Expenses | FIRE Number (3.5%) | FIRE Number (4%) | FIRE Number (5%) |
|---|---|---|---|
| $30,000 | $857,143 | $750,000 | $600,000 |
| $50,000 | $1,428,571 | $1,250,000 | $1,000,000 |
| $75,000 | $2,142,857 | $1,875,000 | $1,500,000 |
| $100,000 | $2,857,143 | $2,500,000 | $2,000,000 |
| $150,000 | $4,285,714 | $3,750,000 | $3,000,000 |
Frequently Asked Questions
Should I use the 4% rule or something more conservative?
For a traditional 30-year retirement starting at 65, the 4% rule has strong historical backing. For early retirement — especially if you’re planning to retire in your 30s or 40s — most financial planners and FIRE practitioners recommend 3% to 3.5%. A longer retirement horizon increases exposure to bad sequence-of-returns scenarios, where early market downturns can permanently deplete a portfolio even if long-term averages remain favorable. Adjusting to 3.5% adds roughly 14% to your required portfolio, which is a meaningful but manageable buffer.
Does this calculator account for Social Security?
Not directly. If you plan to collect Social Security at some point — even at a reduced early retirement benefit — that income offsets your withdrawal needs and effectively lowers your required FIRE number. To account for Social Security, subtract your expected annual benefit from your annual retirement expenses before entering the figure. For example, if you expect $18,000/year from Social Security and your total expenses are $70,000, enter $52,000 as your annual expense target.
What return rate should I use?
The U.S. stock market has historically returned roughly 10% nominally and 7% inflation-adjusted over long periods. For planning purposes, 6–7% is a commonly used real (inflation-adjusted) return. Using a real return means your FIRE number and expense estimates are already in today’s dollars — you don’t need to separately inflate them. If you use a nominal return (10%), you should also inflate your expense target accordingly. Most FIRE calculators, including this one, work most cleanly with real returns and today’s-dollar expenses.
What counts as “savings” for the current savings input?
Include all invested assets: 401k and 403b balances, traditional and Roth IRAs, brokerage accounts, and any other investments you intend to use for retirement income. Don’t include your primary home equity (unless you plan to downsize and invest the proceeds), emergency fund cash, or illiquid assets you wouldn’t draw from in retirement. If you have a pension, treat the estimated annual benefit as described above — subtract it from expenses rather than trying to convert it to a lump sum.
What’s the difference between FI and FIRE?
Financial Independence (FI) means your investments generate enough to cover your expenses — you don’t need to work. Retiring Early (RE) is what you do with that freedom. Many people reach FI and continue working because they enjoy it, shift to part-time or passion projects, or use the security to take career risks they couldn’t before. The FIRE number itself is a FI calculation — what you do after crossing it is entirely up to you.
How do taxes factor in for early retirees?
Tax planning is one of the most underappreciated parts of FIRE strategy. Roth IRA conversions during low-income early retirement years, the Roth conversion ladder, and careful sequencing of taxable versus tax-advantaged withdrawals can dramatically reduce your lifetime tax bill. This calculator estimates gross portfolio size without modeling taxes, so factor in a 10–20% buffer if your savings are primarily in tax-deferred accounts like a traditional 401k or IRA — those withdrawals will be taxed as ordinary income.
Tips for Reaching FIRE Faster
- Track your savings rate, not just your income. The single biggest driver of how fast you reach FIRE is what percentage of your income you save and invest. A 50% savings rate can cut your working years roughly in half compared to a 20% rate.
- Front-load contributions early in the year. Money invested in January has 12 months more to compound than money invested in December. If your cash flow allows, maximize retirement accounts as early in the year as possible.
- Revisit your expenses honestly every year. Your FIRE number is only as accurate as your expense estimate. Lifestyle creep — gradually increasing spending as income grows — is the silent enemy of early retirement timelines.
- Don’t ignore healthcare. Before Medicare eligibility at 65, early retirees must purchase their own health insurance. Budget $500–$1,500 per month per person depending on age, location, and plan — this is often the largest unexpected expense in early retirement plans.
- Consider barista FIRE or coast FIRE as milestones. Coast FIRE is the point at which your current savings will grow to your full FIRE number by traditional retirement age without any additional contributions. Barista FIRE means working part-time to cover current expenses while your portfolio grows. Both are useful intermediate milestones on the path to full FIRE.