When Can You Retire Early?
Calculate your Financial Independence number and how many years until you can retire early. Based on savings rate, investments, and the 4% rule.
The FIRE Formula
Financial Independence, Retire Early (FIRE) is based on a simple formula: save and invest aggressively until your portfolio can sustain your annual expenses indefinitely. Your FIRE number = Annual Expenses ÷ Safe Withdrawal Rate. At a 4% SWR, you need 25x your annual expenses. If you spend $45,000/year, your FIRE number is $1,125,000.
The 4% Rule Explained
The 4% rule comes from the Trinity Study (1998): a portfolio of 50-75% stocks can sustain 4% annual withdrawals (adjusted for inflation) for 30+ years with a 95%+ success rate. More conservative planners use 3.5% (28.6x expenses) and more aggressive use 4.5% (22.2x expenses).
Why Savings Rate Is Everything
Your savings rate determines your timeline more than investment returns. At 10% savings rate, FIRE takes ~40 years. At 30%, about 28 years. At 50%, about 17 years. At 70%, about 8.5 years. The relationship is exponential — small increases in savings rate have outsized impact.
Mr. Money Mustache popularized the insight that a 50% savings rate means you can retire in roughly 17 years regardless of income level. The math works because high savings both builds your portfolio faster AND reduces the amount your portfolio needs to generate.
