How Long Will My Money Last: How to Use It
Portfolio depletion isn't just about the size of your nest egg. It depends on how much you withdraw each year, what your investments earn, how fast prices rise, and how much guaranteed income offsets the draw. This calculator models all four and shows you exactly when the money runs out.
What this calculator does
The portfolio longevity calculator takes your starting balance, monthly withdrawal amount, expected investment return, inflation adjustment rate, and any pension or Social Security income and computes how many years the portfolio lasts before reaching zero. It also calculates the safe withdrawal amount that keeps the portfolio solvent for 30 years, shows return-rate sensitivity at 4%, 6%, and 8% regardless of your base assumption, quantifies how many additional years your pension and Social Security income contribute to portfolio survival, models the impact of reducing monthly spending by $500, and produces a year-by-year table showing the portfolio balance at each age through depletion.
The core insight is that pension and Social Security income don't just supplement your portfolio. They reduce the effective withdrawal rate, which is the single biggest driver of portfolio longevity. A $500,000 portfolio drawing $4,000 per month at 6% lasts about 16 years. The same portfolio drawing $2,500 per month at 6% lasts indefinitely. A $1,500 monthly pension is the difference between running out at 81 and never running out.
What each input means
Starting portfolio balance
The total of all investable assets at the start of retirement: 401(k), 403(b), 457(b), IRA, Roth IRA, and taxable brokerage accounts. Don't include home equity unless you plan to liquidate it. This is the balance that needs to survive your entire retirement. If you're modeling a future scenario rather than today's balance, enter the projected value at your planned retirement date.
Monthly withdrawal amount
The total amount you plan to take from your portfolio each month. This is your gross spending need, not the net after pension income. The calculator subtracts your pension and Social Security from this amount to determine the effective portfolio draw. Enter your full estimated monthly spending here and enter pension and Social Security separately. That way the calculator can show you both what you're spending and how much of it guaranteed income covers.
Expected annual return
The annual investment return you expect on your portfolio throughout retirement. A 60/40 stock and bond portfolio has historically averaged around 6 to 7 percent annually over long periods, though returns in any given decade vary significantly. The calculator runs your base case at this figure and separately shows results at 4%, 6%, and 8% so you can see the full range of outcomes. Most financial planners use 5 to 6 percent for conservative planning purposes.
Annual inflation adjustment
The rate at which your annual withdrawal grows each year to maintain purchasing power. At 2%, a $36,000 annual withdrawal in year one becomes $36,720 in year two and continues compounding. This models the real cost of living increase, not investment return. Setting this to 0% assumes your spending never rises in nominal terms, which overstates how long the portfolio lasts. The Federal Reserve's long-run inflation target is 2%, making 2% a reasonable baseline. Use 3% for a more conservative assumption.
Monthly pension income
Your expected monthly pension payment once it begins. The calculator subtracts this from your monthly withdrawal to compute the effective portfolio draw. Enter 0 if you have no pension. If your pension doesn't start until a few years into retirement, model the bridge period separately by running the calculator twice: once for the pre-pension years with no pension income, then for the post-pension period starting with whatever portfolio balance remains.
Monthly Social Security income
Your expected monthly Social Security benefit at the claiming age you plan to use. Like pension income, this reduces the effective portfolio withdrawal. Get this figure from your Social Security Statement at ssa.gov/myaccount. Use the age-specific estimate for your planned claiming age. Delaying Social Security from 62 to 70 increases the benefit by roughly 76 percent, which substantially reduces the effective portfolio draw during the years you receive it.
Current age
Your age at the start of the simulation. The calculator uses this to label the year-by-year table by age rather than just year number. If you're modeling a future retirement date, enter the age you'll be when you start drawing from the portfolio.
Understanding the outputs
The primary output is the number of years the portfolio lasts and the age at which it reaches zero. If the portfolio survives all 150 simulated years, the calculator reports "Indefinitely" rather than a specific depletion age. Indefinite sustainability happens when your effective withdrawal rate is low enough that investment returns continuously outpace the draw.
The safe withdrawal amount is the largest annual withdrawal that keeps the portfolio solvent for 30 years at your assumed return and inflation adjustment. This is computed independently of your entered withdrawal amount. If your planned withdrawal exceeds the safe amount, the output shows the gap. Closing that gap requires either more savings, lower spending, later retirement, or more guaranteed income.
The pension years added and Social Security years added figures show how much guaranteed income extends portfolio life compared to funding all spending from the portfolio alone. These numbers can be striking. A $1,800 monthly pension can add 15 or more years to portfolio survival for a $400,000 portfolio. This is why public employees with defined benefit pensions frequently achieve long-term financial security with substantially smaller investment balances than comparable private-sector retirees.
The year-by-year table shows your portfolio balance at the start of each year, the withdrawal amount for that year (growing with inflation), the investment growth, and the ending balance. Look for the year where the ending balance first drops below your annual withdrawal. That's the point of maximum vulnerability, where a bad return year could accelerate depletion. The table shows up to 15 rows by default and can be expanded to show all 40 simulated years.
The $500 monthly reduction scenario shows the portfolio survival extension from spending $500 less each month. It's often more than people expect. This reinforces that small, sustained reductions in spending have outsized effects on retirement security.
Sequence-of-returns risk
The calculator uses a fixed annual return assumption, which means it doesn't model sequence-of-returns risk directly. In reality, the order of returns matters enormously. A portfolio that earns -20%, +30%, +10% over three years produces a very different outcome than one earning +10%, +30%, -20% even though the average return is identical. Retirees who face a major market downturn in their first five years suffer permanent portfolio impairment that average returns don't undo.
To approximate sequence risk, run the calculator at a return 2 percentage points below your expected average and treat that as your planning floor. If the portfolio still lasts 30 or more years at that lower return, your plan has real cushion against a bad start. The 4% return sensitivity scenario serves this stress-test purpose.
Related calculators
Frequently asked questions
How does pension income affect how long my portfolio lasts?
Pension income reduces the effective amount your portfolio must fund each year. If you spend $4,000 per month and a pension covers $1,500, the portfolio only needs to provide $2,500. That lower effective withdrawal rate can add 10 to 20 years to portfolio survival. The calculator shows how many additional years your pension and Social Security each contribute.
What is the safe withdrawal amount?
The largest annual withdrawal that keeps the portfolio solvent for at least 30 years at your assumed return and inflation rate. The calculator finds this through binary search. If your planned withdrawal is above this figure, your retirement plan depends on either earning above-average returns or running the portfolio close to zero before your planning horizon ends.
What does the return rate sensitivity show?
How many years the portfolio lasts at 4%, 6%, and 8% returns regardless of your base case. A plan that still works at 4% is stress-tested against a sustained low-return environment. A plan that only works at 7% or 8% requires above-average market performance throughout retirement, which is a significant risk for anyone facing a 25-year or longer withdrawal period.
What does reducing withdrawal by $500 per month do?
Cutting $500 per month reduces the annual portfolio draw by $6,000. For a $400,000 portfolio, this can add 8 to 12 or more years to survival depending on your return assumption. The output shows the specific additional years your portfolio gains from that reduction. Small spending cuts have large longevity effects because the portfolio is largest in early retirement when compounding has the most time to work.
How does the inflation adjustment affect the calculation?
The inflation adjustment increases your withdrawal each year. At 2%, a $3,000 monthly withdrawal becomes $3,060 in year two and keeps rising. Setting this to zero overstates portfolio longevity by ignoring spending growth. The gap between your return rate and inflation adjustment is your real return, the driver of long-term portfolio sustainability. A 6% return with 3% inflation is effectively a 3% real return, which is more conservative than it sounds.