Retirement Savings Calculator

Years of Income is calculated as your Retirement Balance divided by your Annual Withdrawal, and Annual Withdrawal is itself your balance multiplied by the Withdrawal Rate — so the balance cancels out of the math entirely, leaving 1 divided by the withdrawal rate as the answer. At the default 4% rate that's always 25 years, whether your balance is $200,000 or $2 million; only changing the Withdrawal Rate itself changes this figure.

It's a widely cited retirement withdrawal guideline, originating with William Bengen's 1994 research in the Journal of Financial Planning and later confirmed by the 1998 Trinity Study, suggesting that withdrawing about 4% of a retirement portfolio's initial value each year (adjusted for inflation) has historically had a strong chance of lasting a 30-year retirement without depleting the portfolio. It's a rule of thumb built on historical US market data, not a guarantee — actual safe withdrawal rates are debated and depend on the market conditions you retire into.

Retirement Balance is the raw, nominal dollar amount your account is projected to hold at retirement. Balance (Today's Dollars) discounts that same figure by your assumed inflation rate compounded over the years until retirement, showing what that future sum would actually buy at today's prices — a large nominal balance decades from now can represent meaningfully less real purchasing power than the sticker number suggests.

Yes — it applies one fixed monthly rate of return, derived from your entered annual return, consistently across every month until retirement. Real markets don't move smoothly; some years are up sharply, others down. This averages out that variability, which makes for an easy-to-follow projection but doesn't capture how a bad sequence of early losses can affect a real portfolio differently than a smooth average would suggest.

Retirement age sets how many years your contributions have to compound before withdrawal begins, and because compounding accelerates over time, even a few additional years can produce a substantially larger balance — the growth in later years, on a larger base, dwarfs the growth in early years on a smaller one. At the default settings, retiring one year later raises the projected balance by roughly 9%. It is not the single most powerful lever, though: a half-point change in the Expected Return assumption moves the projection somewhat more than a one-year change in retirement age does, which is why the return figure deserves at least as much scrutiny as the retirement date.