FIRE Calculator

Financial Independence Retire Early (FIRE) calculator — find out when you can retire based on your savings rate. This tool processes all data locally in your browser. No information is ever sent to any server. Completely free, no registration required.

How to Use the FIRE Calculator

1. Enter your input values above
2. Results update automatically
3. Copy or download the output

What is a FIRE Calculator?

A FIRE (Financial Independence, Retire Early) Calculator models how quickly you can achieve financial independence — the point where your investment portfolio generates enough passive income to cover your living expenses indefinitely. The FIRE movement, popularized by the Trinity Study and the 4% Rule, has evolved into multiple approaches by 2026: LeanFIRE (retiring on $25-40K/year), regular FIRE (targeting 25× annual expenses), FatFIRE ($100K+/year), and CoastFIRE (having enough invested that it'll grow to your target without further contributions). This calculator shows your FI number, years to FI, and the trade-offs between saving rate and time to freedom.

How Does It Work?

Enter your annual income, annual expenses (which determines your savings rate), current portfolio value, and expected investment return. The calculator first determines your FI number: Annual Expenses × 25 (inverse of the 4% Rule). Then it projects how long until your portfolio reaches that number, given your annual savings and compound returns. The key insight: savings rate, not income, determines time to FI. Someone saving 50% of their income reaches FI much faster than someone saving 15% of a higher income.

Formula

FI Number = Annual Expenses × 25\nYears to FI = log(1 + (FI Number × r) / Annual Savings) / log(1 + r)\n\nWhere r = annual real return (after inflation)\n\nSavings Rate = (Income − Expenses − Taxes) ÷ Income × 100%\nSafe Withdrawal = Portfolio × 4% (year 1, inflation-adjusted after)\n\nCoastFI: Age CI = ln(FI Number / Current Portfolio) / ln(1 + r)\n(age at which portfolio reaches FI without further contributions)

Who Uses This Tool?

• Workers calculating their FI number and target retirement date
• Couples aligning on savings rate and lifestyle design
• Career changers evaluating when they can afford to take a lower-paying job
• CoastFIRE candidates checking if their portfolio can grow without more contributions
• Budgeting: seeing how increasing savings rate by 5% shaves years off FI date

Pro Tips

• The 4% Rule was designed for 30-year retirements. For early retirees (40+ year horizon), consider a 3.25-3.5% withdrawal rate for higher safety margin
• Increasing your savings rate from 15% to 20% can shave 5-7 years off your FI timeline. From 30% to 50% can shave 10+ years
• Don't forget healthcare costs in your FI budget. ACA plans or health-sharing ministries can cost $300-800/month for individuals pre-Medicare
• Geo-arbitrage (retiring in a lower-cost country) can halve your required FI number. Many FIRE adherents spend time in Mexico, Portugal, Thailand, or Eastern Europe

Frequently Asked Questions about FIRE Calculator

How much do I need to retire early?

The standard rule: 25× your annual expenses (= 4% withdrawal rate). If you spend $40,000/year, you need $1 million. For early retirement (40+ years), aim for 30-33× expenses (3-3.3% withdrawal). Track your actual expenses for 1-2 years before committing.

What is CoastFIRE?

CoastFIRE is when your existing investments will grow to your FI number by your target retirement age WITHOUT further contributions. For example, $200K invested at 7% real return for 25 years grows to $1.08M. You 'coast' by working only enough to cover current expenses.

Free online FIRE Calculator — no signup, 100% client-side processing. All data stays in your browser.