Retirement Calculator

What this calculator does

This retirement calculator projects what your savings grow into by the age you plan to stop working, then translates that balance into the monthly income it can sustainably produce. You supply your current age, retirement age, existing savings, monthly contribution, expected return, and the withdrawal rate you want to plan around. It returns the nest egg at retirement, the income that nest egg supports, and a year-by-year table separating what you contributed from what the market added.

That contributions-versus-growth split is the part worth reading. In the early years almost the entire balance is money you put in. Somewhere in the second or third decade growth overtakes contributions permanently, and from then on the portfolio does more of the work than you do.

When to use it

The natural moment is when you are setting a contribution rate: at open enrollment, after a raise, or when a new job first gives you access to a 401(k). Working backwards from a target monthly income to the contribution that produces it turns an abstract percentage into a decision you can act on this month.

It is also the right tool for the retire-early question. Running retirement at 62 against 67 shows both effects at once, since you lose five years of compounding on your largest ever balance and add five years the portfolio must fund. And it prices the choice between putting a bonus into the market or against the mortgage.

Understanding the inputs

Current savings should be every retirement-earmarked dollar you hold, including 401(k) balances, Traditional and Roth IRAs, and any taxable brokerage you would genuinely draw on. Monthly contribution should include the employer match, because matched money compounds identically to your own and omitting a typical 3 percent match understates a 30-year projection substantially.

Expected return swings the result harder than any other field. Seven percent nominal is defensible for a diversified stock-heavy portfolio and anything above 8 is optimistic. Withdrawal rate should reflect how long the money has to last: 4 percent for a retirement starting around 65, closer to 3.5 percent if you intend to stop in your fifties.

How is this calculated?

FV = PV(1+r)^n + PMT×[(1+r)^n − 1]/r. Nest Egg Needed = Monthly Income / Withdrawal Rate.

A worked example

A 35-year-old with $85,000 saved, contributing $800 a month at 7 percent, reaches roughly $1,936,000 by age 67. Only about $392,000 of that is money they contributed; the remaining $1.54 million is growth. At a 4 percent withdrawal rate the portfolio supports around $77,400 a year, or roughly $6,450 a month, before any Social Security.

Raise the contribution to $1,200 a month and the balance rises to about $2,507,000. Alternatively, retire at 62 on the original $800 and it falls to roughly $1,325,000. Five years of earlier retirement costs around $611,000, because those are precisely the years the largest balance would have been compounding.

Limitations and assumptions

This is a projection under fixed assumptions, not a prediction. It applies one constant return every single year, which no real portfolio delivers. Markets arrive in sequences, and the order matters enormously: a bad decade immediately after you retire damages a portfolio far more than the same decade in the middle, even at an identical average. A single-figure output cannot show that risk.

It also ignores taxes on withdrawals, Social Security, healthcare costs before Medicare eligibility at 65, and any change in your contribution across a career. Treat the number as the center of a wide range rather than a target, and rerun it whenever your circumstances shift.