How Much Do I Need to Retire? A Simple Calculator Guide

Retirement projections use two formulas. The first grows your existing savings: FV = PV x (1 + r)^n, where PV is present value, r is the periodic return, and n is the number of periods. The second grows your regular contributions (the annuity formula): FV = PMT x [((1 + r)^n - 1) / r].

Your total projected nest egg is the sum of both. The Retirement Savings Calculator combines these two formulas for you. Enter your current age, retirement age, current savings, monthly contribution, expected return, and inflation rate.

The 4% rule is a guideline from the Trinity Study. It says that if you withdraw 4% of your portfolio in Year 1 of retirement and then adjust for inflation each year, your money should last roughly 30 years.

Working backward: if you need $50,000 per year in retirement (in today's dollars), you need $50,000 / 0.04 = $1,250,000 at retirement. That is your target. Adjust up or down based on your desired lifestyle, pension income, or Social Security benefits.

Maria is 28 years old. She has $15,000 saved, contributes $400/month, expects 7% average annual returns, plans to retire at 65, and assumes 3% inflation.

Years until retirement: 37. Using the compound interest formulas: her $15,000 grows to approximately $185,000. Her $400/month contributions grow to approximately $850,000. Total nominal portfolio: about $1,035,000.

Adjusted for inflation: $1,035,000 / (1.03)^37 = roughly $347,000 in today's dollars. Under the 4% rule, that supports about $13,900/year in today's purchasing power — likely not enough alone, but combined with Social Security and possible pension, it forms a solid base.

If Maria waits until age 35 to start (same $15,000 starting point, same $400/month), she has only 30 years instead of 37. Her total drops to about $640,000 nominal — a loss of nearly $400,000. Those 7 "lost" years represent the most powerful compounding period.

The lesson: you cannot make up for lost time by saving more later. Time is the most powerful variable in compound interest. Even $100/month starting at 22 beats $500/month starting at 35 over a 40+ year horizon.

Ignoring inflation is the biggest one. $1 million sounds like a lot, but in 30 years at 3% inflation, it has the purchasing power of about $412,000. Always think in today's dollars.

Not accounting for healthcare costs is another gap. Out-of-pocket healthcare expenses in retirement can run $300,000+ per couple. Factor this into your target number. Finally, relying solely on Social Security is risky — benefits cover roughly 40% of pre-retirement income for the average worker.