Retirement & FIRE Number Calculator
Calculate your target retirement corpus, monthly savings required, and years to financial independence.
How to Use the Retirement & FIRE Calculator
Planning for retirement doesn’t have to be guesswork. Whether you plan to retire early (the FIRE Movement: Financial Independence, Retire Early) or retire comfortably at traditional age 65, this interactive tool estimates your target nest egg using established wealth-building principles.
1. What is the 4% Rule and the 25x Formula?
The 4% Rule (derived from the landmark Trinity Study) suggests that if you withdraw 4% of your total investment portfolio in your first year of retirement, and adjust for inflation thereafter, your portfolio has an overwhelming probability of lasting 30+ years.
In simple math, dividing 100 by 4 equals 25x. That means your minimum retirement number is roughly 25 times your annual living expenses. For example, if you need $48,000 per year to cover your mortgage, food, healthcare, and travel, your target nest egg is $1,200,000 ($48,000 × 25).
2. Factoring in Investment Returns and Compound Interest
The stock market (historically measured by broad index funds like the S&P 500) has returned roughly 8% to 10% annually before inflation. By investing consistently into tax-advantaged accounts (such as a 401(k), Roth IRA, or HSA), your monthly contributions benefit from exponential compound interest.
For a detailed breakdown of honest retirement savings numbers, read our comprehensive guide: How Much Do I Need to Retire? The Honest Calculation.