Retirement Savings Calculator
Calculate how much your retirement savings will grow and your monthly income in retirement.
Enter your values and click Calculate
This retirement savings calculator projects your portfolio value at retirement using compound growth, then estimates your sustainable monthly income using the 4% withdrawal rule — the widely cited guideline from the Trinity Study suggesting that withdrawing 4% of your portfolio annually has historically supported 30-year retirements without depleting savings. Enter your current age, target retirement age, existing savings, monthly contribution, and expected annual return to see your projected portfolio value, total contributions, total investment growth, and estimated monthly retirement income. The calculator uses annual compounding for contributions and existing savings. The 4% rule provides a conservative starting estimate — actual withdrawal strategies may differ based on market conditions, Social Security income, pension benefits, and personal spending needs. This tool is for educational planning purposes; consult a financial advisor for personalized retirement planning.
How It Works
The calculator uses two compound growth formulas. Future value of existing savings: FV = P × (1 + r)^t, where P is current savings, r is annual return, and t is years to retirement. Future value of monthly contributions uses the annuity formula: FV = PMT × [(1 + r/12)^(12t) - 1] / (r/12), where PMT is monthly contribution and r/12 is monthly rate. These two values are summed for total projected portfolio. Monthly retirement income is estimated using the 4% rule: annual withdrawal = portfolio × 0.04, divided by 12. The 4% rule comes from the Trinity Study (1998), which found that a 4% annual withdrawal from a diversified portfolio had a very high probability of lasting 30+ years across historical market conditions. It is a planning guideline, not a guarantee.