Calculate Fire Number

FIRE Number Calculator

Enter your details and click 'Calculate' to see your FIRE number and estimated time to financial independence.

function calculateFireNumber() { var annualExpenses = parseFloat(document.getElementById("annualExpenses").value); var safeWithdrawalRate = parseFloat(document.getElementById("safeWithdrawalRate").value); var currentSavings = parseFloat(document.getElementById("currentSavings").value); var annualSavings = parseFloat(document.getElementById("annualSavings").value); var investmentGrowthRate = parseFloat(document.getElementById("investmentGrowthRate").value); var resultDiv = document.getElementById("fireResult"); // Input validation if (isNaN(annualExpenses) || annualExpenses <= 0) { resultDiv.innerHTML = "Please enter a valid annual expense amount greater than 0."; return; } if (isNaN(safeWithdrawalRate) || safeWithdrawalRate 100) { resultDiv.innerHTML = "Please enter a valid safe withdrawal rate (e.g., 4 for 4%)."; return; } if (isNaN(currentSavings) || currentSavings < 0) { resultDiv.innerHTML = "Please enter a valid current savings amount."; return; } if (isNaN(annualSavings) || annualSavings < 0) { resultDiv.innerHTML = "Please enter a valid annual savings contribution."; return; } if (isNaN(investmentGrowthRate) || investmentGrowthRate = fireNumber) { yearsToFire = 0; // Already reached FIRE } else if (annualSavings <= 0 && growthRateDecimal <= 0) { yearsToFire = -1; // Will never reach if not saving and not growing } else { var maxYears = 200; // Prevent infinite loops for unrealistic scenarios while (currentPortfolio < fireNumber && yearsToFire = maxYears) { yearsToFire = -2; // Indicate "more than maxYears" } } // Format results var formattedFireNumber = fireNumber.toLocaleString('en-US', { style: 'currency', currency: 'USD', maximumFractionDigits: 0 }); var formattedCurrentSavings = currentSavings.toLocaleString('en-US', { style: 'currency', currency: 'USD', maximumFractionDigits: 0 }); var formattedAnnualSavings = annualSavings.toLocaleString('en-US', { style: 'currency', currency: 'USD', maximumFractionDigits: 0 }); var yearsToFireText; if (yearsToFire === 0) { yearsToFireText = "You have already reached your FIRE number!"; } else if (yearsToFire === -1) { yearsToFireText = "Given your current savings and growth, you will likely never reach your FIRE number without additional savings or higher returns."; } else if (yearsToFire === -2) { yearsToFireText = "It would take more than " + maxYears + " years to reach your FIRE number with these inputs. Consider increasing savings or expected returns."; } else { yearsToFireText = "Approximately " + yearsToFire + " years."; } resultDiv.innerHTML = "

Your FIRE Number: " + formattedFireNumber + "

" + "This is the total amount you need invested to cover your annual expenses based on your chosen safe withdrawal rate." + "

Estimated Time to FIRE:

" + "" + yearsToFireText + "" + "(Based on current savings of " + formattedCurrentSavings + ", annual savings of " + formattedAnnualSavings + ", and an expected " + investmentGrowthRate + "% annual investment growth.)"; }

Understanding Your FIRE Number

The concept of FIRE (Financial Independence, Retire Early) has gained significant traction for those aspiring to take control of their financial future and achieve early retirement. At the heart of the FIRE movement is the "FIRE Number" – the total amount of money you need to accumulate in your investment portfolio to cover your living expenses indefinitely, allowing you to stop working if you choose.

How is the FIRE Number Calculated?

The most common method for calculating your FIRE number is based on the "4% Rule." This rule suggests that you can safely withdraw 4% of your investment portfolio each year, adjusted for inflation, without running out of money over a typical 30-year retirement period. While not a guarantee, historical data supports its robustness.

The formula is straightforward:

FIRE Number = Annual Expenses / Safe Withdrawal Rate

For example, if your estimated annual expenses in retirement are $50,000 and you plan to use a 4% safe withdrawal rate, your FIRE number would be:

$50,000 / 0.04 = $1,250,000

This means you would need $1.25 million invested to generate $50,000 per year in passive income.

Key Inputs Explained:

  • Estimated Annual Expenses in Retirement: This is arguably the most critical input. It's not your current spending, but what you realistically expect to spend annually once you're financially independent. Be honest and thorough, considering housing, food, healthcare, travel, hobbies, and other lifestyle costs. Lowering your expenses is often the fastest way to reduce your FIRE number.
  • Safe Withdrawal Rate (%): While 4% is the widely accepted benchmark, some FIRE enthusiasts opt for a more conservative 3.5% or even 3% for added security, especially if they plan for a very long retirement (e.g., retiring in their 30s or 40s). A lower withdrawal rate means a higher FIRE number but also a lower risk of running out of money.
  • Current Investment Savings ($): This is the total amount you have already accumulated in investment accounts (e.g., 401k, IRA, brokerage accounts). It gives you a starting point for your journey to FIRE.
  • Annual Savings Contribution ($): The amount you consistently save and invest each year. The higher this number, the faster you will reach your FIRE number.
  • Expected Annual Investment Growth Rate (after inflation, %): This is your anticipated average annual return on your investments, net of inflation. A common assumption for a diversified portfolio of stocks and bonds is 5-7% after inflation. This rate significantly impacts how quickly your portfolio grows towards your FIRE number.

Why Calculate Your FIRE Number?

Knowing your FIRE number provides a clear, tangible goal for your financial planning. It transforms the abstract idea of "saving for retirement" into a concrete target. By understanding how your expenses, savings rate, and investment returns influence this number, you can make informed decisions to accelerate your path to financial independence.

Use the calculator above to determine your personal FIRE number and get an estimate of how many years it might take you to achieve financial independence based on your current trajectory. Remember, these are estimates, and consistent saving and smart investing are key to reaching your goals.

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