Your portfolio will last
until age
Comfortable (past age 85)· Withdrawing $4,500/mo ($54,000/yr)
Tap the number to set a target — we'll recalculate your withdrawal.
Portfolio over time
Drag to adjust target depletion age89 yrs old
Tap the number to set a target — we'll recalculate your withdrawal.
The question sounds simple, but it's really five inputs pulling against each other: how much you've saved, how old you are when withdrawals start, how much you take out each month, how your investments perform, and how many years the money needs to cover. Change any one of them and the answer moves, sometimes by a little, sometimes dramatically.
At the center of it is a single relationship: the gap between growth and withdrawals. Every month, your balance earns a return, and then your withdrawal comes out. If the growth is larger than the withdrawal, the balance rises even after you take money out, and it can keep doing that indefinitely. If the withdrawal is larger than the growth, the balance falls a little every month, slowly at first and then faster as there's less capital left to generate growth. That's the entire mechanism behind every result this calculator produces.
Compounding is what makes the timing of that gap matter so much. A balance that shrinks by 1% a month doesn't shrink at a steady dollar amount — the monthly withdrawal stays fixed, but the monthly growth on a shrinking balance keeps getting smaller, so more of each withdrawal comes from principal as time passes. That's why the last few years of a depleting projection often look like they're falling off a cliff, even though the withdrawal never changed.
Starting from whichever is later — your current age or your planned retirement age — the calculator steps forward one month at a time. In each month it applies your annual return (converted to a monthly rate) to the current balance first, and then subtracts your monthly withdrawal. That order matters: growth is calculated on the balance you had at the start of the month, not on the balance after money has already left the account.
After each month's growth and withdrawal, the balance is checked against zero. The first month the balance would fall to or below zero, the simulation stops and records that as the depletion point — it doesn't let the balance go negative, since a negative balance isn't a real state for a savings account. This process repeats for up to 70 years, which is long enough to cover the vast majority of realistic retirement lengths.
The ∞ symbol appears when your monthly growth at the start of retirement — your balance multiplied by your annual return, divided by 12 — is already equal to or greater than your monthly withdrawal. In that case, the gap between growth and withdrawals never turns negative, so the 70-year simulation never finds a depletion month and the balance is projected to hold or grow indefinitely under those exact assumptions.
The calculator starts you at a 5% annual return because it's a common, round planning figure for a diversified, moderate-risk portfolio — not because it's a prediction. It's an editable assumption, the same as any other field on this page, and it deserves to be questioned rather than accepted by default.
Real investment returns don't arrive as a smooth 5% every single year. Some years are sharply positive, some are negative, and the long-run average is only visible after many years have passed. This calculator applies one constant monthly rate for the entire projection, which is a simplification that can't capture that unevenness — it will always look smoother than an actual portfolio ever will.
Because of that, it's worth deliberately testing lower numbers. Try 3% or 4% instead of 5% and see how many years that removes from your projection, or how it changes an "indefinite" result into one with a depletion age. A plan that still holds up at a more conservative return gives you a better sense of your real margin than a single optimistic run.
The examples below use a 5% annual return and this calculator's exact monthly-compounding math, so you can reproduce them by entering the same numbers above.
At the start, this balance generates about $2,083 a month in growth (5% ÷ 12 × $500,000), which is less than the $2,500 withdrawal. The shortfall is small, so the balance declines slowly at first — this projection lasts roughly 36 years, illustrating how a withdrawal only slightly above the growth rate can still fund a very long retirement.
Raising the same balance's withdrawal to $3,500 a month — 40% more — cuts the projected duration to roughly 18 years. The growth rate hasn't changed, but a much larger share of every withdrawal now has to come from principal, which shows how withdrawal size, not balance size, is often the more decisive variable.
A $1,000,000 balance generates about $4,167 a month in growth at 5%, which is more than the $4,000 withdrawal. Because growth covers the withdrawal every month, the calculator shows this balance lasting indefinitely — the clearest illustration of the growth-versus-withdrawal threshold this whole tool is built around.
This calculator is a simplified model, and several real-world factors can push your actual experience away from its projection:
When the calculator shows the infinity symbol, it means that at your entered return, balance, and withdrawal, monthly growth is projected to be greater than or equal to your monthly withdrawal for the entire 70-year window it simulates — so the balance never trends toward zero. It is a statement about the arithmetic of the inputs you chose, not a guarantee about the future.
An indefinite result can still turn into a depleting one if any of the inputs change: a lower actual return, a higher withdrawal, new taxes, or inflation-driven spending increases can all tip the balance from growing to shrinking. Treat "indefinite" as a sign you have a margin under today's assumptions, and re-check it periodically as your actual returns and spending become known.
The calculator simulates your portfolio one calendar month at a time, starting from whichever is later, your current age or your planned retirement age. In each month, it first applies your annual return — divided by 12 to get a monthly rate — to the existing balance, and then subtracts your fixed monthly withdrawal. Depletion is recorded at the first month the balance would fall to or below zero; the balance is not allowed to go negative, and the partial final month is treated as the end of the projection.
The simulation runs for up to 70 years past the retirement age. If the balance hasn't depleted by then and monthly growth is still at least equal to the monthly withdrawal, the result is shown as lasting indefinitely rather than projected further, since multi-decade nominal-dollar projections beyond that point carry limited practical meaning. Displayed years and ages are rounded for readability; the underlying month-by-month figures are used for the chart and for solving a target withdrawal or age.
Some limitations worth keeping in mind:
Last updated August 2026.