liminfoFIRE Calculator
Free web tool: FIRE Calculator
FIRE Target Amount
900,000,000
Annual Expenses x 25
Savings Rate
40.0%
Years to FIRE
22 yrs
Age 52
Monthly Safe Withdrawal (4%)
3,000,000
About FIRE Calculator
The FIRE Calculator helps you determine how much money you need to achieve Financial Independence and Retire Early (FIRE). It computes the FIRE target amount using the widely accepted 25x rule (annual expenses multiplied by 25, derived from the 4% safe withdrawal rate), your years to FIRE based on current savings, annual income, annual expenses, expected real investment return, and inflation rate.
This tool is used by personal finance enthusiasts, early retirement planners, and anyone following the FIRE movement — which includes sub-movements like Lean FIRE, Fat FIRE, Barista FIRE, and Coast FIRE. By entering your current age and financial figures, you can see the exact retirement age you are on track to achieve and how much you can safely withdraw each month without depleting your portfolio.
The calculation engine iterates year by year from your current savings, applying the real return rate (expected return minus inflation) and adding the annual surplus (income minus expenses). The first year your projected portfolio reaches or exceeds the FIRE target (annual expenses × 25) is recorded as your FIRE date. The monthly safe withdrawal is then computed as FIRE target × 4% / 12, representing the sustainable monthly income from your portfolio in retirement.
Key Features
- Computes FIRE target amount as annual expenses × 25 (the 4% safe withdrawal rule)
- Calculates savings rate as (income - expenses) / income × 100 for quick financial health check
- Year-by-year portfolio simulation applying real return (return minus inflation) iteratively
- Displays years to FIRE and exact projected retirement age based on current inputs
- Shows monthly safe withdrawal amount (4% of FIRE number / 12) for post-retirement budgeting
- Separate inflation rate input to compute real returns and avoid overestimating purchasing power
- Handles up to 60-year simulation horizon to cover a wide range of starting ages and savings rates
- 100% client-side processing — your financial data never leaves your browser
Frequently Asked Questions
What is the FIRE number and how is it calculated?
The FIRE number is the total portfolio value you need to retire safely. It is calculated as your annual expenses multiplied by 25, which is derived from the 4% safe withdrawal rate. For example, if you spend $40,000 per year, your FIRE number is $1,000,000. Once your investments reach this amount, you can withdraw 4% annually (adjusted for inflation) and historically your portfolio will last 30+ years.
What is the 4% safe withdrawal rate?
The 4% rule originates from the Trinity Study (1998), which analyzed historical US stock and bond returns. It found that retirees who withdrew 4% of their initial portfolio per year, adjusted for inflation, had a very high probability of not running out of money over a 30-year retirement. While critics note it may be conservative for 50+ year retirements, it remains the most widely cited benchmark in FIRE planning.
What does "real return" mean in this calculator?
Real return is the investment return after subtracting inflation. If your portfolio grows at 7% per year but inflation is 3%, your real return is approximately 4%. The calculator uses real return to simulate portfolio growth in today's purchasing-power terms, preventing the overestimation of future wealth that would occur if nominal returns were used without inflation adjustment.
What is a savings rate and why does it matter for FIRE?
Savings rate is the percentage of your income that you save and invest: (income - expenses) / income × 100. It is the single most powerful lever in FIRE planning. A 50% savings rate means you can retire in roughly 17 years from zero savings; a 70% savings rate reduces that to about 8.5 years. Higher savings rates both accelerate wealth accumulation and reduce the FIRE target by lowering your assumed annual expenses.
What are the sub-types of FIRE?
Lean FIRE: retire on a very frugal budget (typically under $40,000/year). Fat FIRE: retire with a high-spending lifestyle ($100,000+/year). Barista FIRE: semi-retire with part-time work to cover basic expenses while investments grow. Coast FIRE: save enough early that compound growth alone will reach your FIRE number by traditional retirement age without further contributions.
Why does the calculator require the return rate to be greater than inflation?
If the inflation rate equals or exceeds the investment return rate, the real return is zero or negative. In that scenario, your purchasing power does not grow and you would never reach a FIRE target. The calculator requires a positive real return (return > inflation) to produce a meaningful simulation. If you enter equal values, the tool returns null to prevent a misleading result.
How accurate is this FIRE calculator?
The calculator provides a deterministic projection based on fixed average return and inflation rates. Real-world portfolios experience sequence-of-returns risk, market volatility, and changing personal circumstances. Use this tool for directional planning and motivation. For comprehensive FIRE planning, also consider Monte Carlo simulations, variable withdrawal strategies, and consultation with a financial advisor.
Can I use this calculator if I am already past 40 or have existing savings?
Absolutely. The calculator accepts any current age and any amount of existing savings. It simulates growth starting from your current savings position. If you already have a substantial portfolio, the time to FIRE may be much shorter than if starting from zero, and the calculator will accurately reflect that in the projected years to FIRE and retirement age.