Retirement Calculator

How your retirement savings grow over time

Retirement accounts grow through two engines working together: the balance you already have compounding on its own, and the new money you add every month compounding from the moment it lands. This calculator projects both pieces forward at your expected annual return, converted to a monthly rate, until the month you turn your chosen retirement age. Because each month's growth is calculated on the prior month's larger balance, the curve starts gently and steepens noticeably in the final stretch—the hallmark of long-run compounding.

Current balance, contributions, and the employer match

Your current balance grows on its own at the monthly rate for the full number of months remaining. Your monthly contributions are modeled as an annuity-due—deposited at the start of each month so each one gets a full month of growth before the next arrives. If your plan includes an employer match, the calculator folds it directly into the deposit: a 50% match turns a $500 contribution into a $750 effective monthly deposit, and that larger figure is what actually compounds. The results panel then splits the final balance back out so you can see your contributions, the employer's contributions, and the investment growth on top of both, separately.

Worked example — 30 years to retirement at 7%

Picture a 35-year-old with $25,000 already saved, adding $500 a month, receiving a 50% employer match (an extra $250, for a $750 total monthly deposit), and assuming a 7% expected annual return until age 65. That is 30 years, or 360 months, at a monthly rate of roughly 0.583%. The current balance alone would grow to a meaningful sum on its own, and the steady $750 monthly deposits—compounding from day one—end up contributing far more than the sum of the deposits themselves once decades of growth are layered on top. Try these numbers (or your own) in the form above to see the full split between your contributions, the match, and the growth.

How much do you actually need to retire? (the 25x / 4% rule)

A widely cited rule of thumb says you should aim for a nest egg of roughly 25 times your expected annual spending, which historically supported an initial withdrawal rate near 4% without running out of money over a long retirement. If you expect to spend $50,000 a year in retirement, that rule points to a target near $1.25 million in today's dollars. The rule is a starting point, not a guarantee—your real number depends on how long you expect to live, what other income (pensions, Social Security, rental income) you will have, and how your spending changes over time. Use the projected nest egg from this calculator as one input into that bigger picture, not the final word.

Why returns, taxes, and inflation matter

The expected annual return you choose has an outsized effect on the final number because it compounds on an ever-larger base for decades—small changes in the assumed rate can swing the projected nest egg by a wide margin, which is why it is worth testing both a conservative and an optimistic scenario. Just as important is what this calculator does not show: it reports a nominal dollar figure, with no adjustment for income tax on withdrawals, no allowance for inflation eroding purchasing power over thirty-plus years, and no modeling of contribution limits, account fees, salary growth, or Social Security and pension income. Treat the headline number as a rough, pre-tax, today's-dollars estimate, and remember that your real spending power at retirement will likely be lower than it appears here.

How to read your results

The projected nest egg is the headline figure: your estimated balance on the month you reach your chosen retirement age. Below it, your total contributions shows how much of that balance came directly from your own paycheck, while employer match total isolates the "free money" your employer added on top. Investment growth is everything left over—the compounding effect on both your starting balance and every deposit along the way—and is usually the largest slice over a long enough horizon. Finally, years until retirement simply restates how long your plan has to compound, which is often the single biggest lever you control.

Disclaimer — estimate only, not financial advice

This tool produces an educational estimate based on simplified, constant assumptions—not a forecast, guarantee, or personalized financial, retirement, tax, or investment advice. Real markets fluctuate, contribution limits and employer plan rules vary and change, and this projection does not model taxes, inflation, fees, salary growth, withdrawals, or Social Security and pension income. Investment returns are never guaranteed. For decisions about your actual retirement accounts, speak with a qualified, licensed financial professional who can review your full situation.