Does this calculator model inflation or cost-of-living adjustments?

No. All figures are in nominal dollars with a fixed monthly withdrawal. To approximate inflation, you can either reduce your withdrawal target to leave a safety margin or run separate scenarios with increasing withdrawals over time.

How should I choose the annual return during payout?

Use an estimate that reflects your actual asset allocation and risk tolerance, but err on the conservative side—especially in retirement, where large early losses can hurt sustainability. Many planners test scenarios in the 3–5% range for diversified portfolios.

What does it mean if monthsLasted is blank or extremely large?

That usually means your monthly withdrawal is at or below the expected monthly interest, so the balance does not deplete in the simulation horizon. While that suggests a potentially sustainable payout, real-world volatility and inflation still matter, so you should treat it as a hopeful sign, not a guarantee.

Can I use this instead of a full retirement plan?

No. This is a quick, high-level tool to understand how withdrawal levels interact with balances and returns. A full plan should consider taxes, Social Security, pensions, other accounts, and detailed cash-flow projections.

finance calculator

Retirement Payout Duration

See how long a balance lasts with a fixed monthly withdrawal and an assumed annual return, plus total interest earned during that period.

Results

Years the balance lasts: 27.58
Months the balance lasts: 331
Total interest earned: $325,332

How to use this calculator

Enter your current retirement account balance you plan to draw from (or combine multiple accounts into one total if you want a consolidated view).
Enter the annual rate of return you expect during the withdrawal phase, reflecting your actual asset mix and risk tolerance.
Enter the fixed monthly withdrawal amount you plan to take from the account.
Review the estimated number of years and months until the balance is exhausted under these assumptions.
Review the total interest earned over that period, which shows how much investment growth contributed to your withdrawals.
Adjust the withdrawal amount, expected return, or starting balance to explore different payout durations and see how sensitive your plan is to each variable.

Inputs explained

Retirement balance: The starting balance of the account you’ll be drawing from, in dollars. You can enter a single account or a combined balance across multiple accounts if they are invested similarly.
Annual return during payout (%): Your assumed average annual rate of return while you are withdrawing from the account. Use a conservative estimate, as actual markets can be volatile, especially during retirement.
Monthly withdrawal: The fixed dollar amount you plan to withdraw from the account each month. This tool assumes the withdrawal stays constant over time and does not adjust for inflation.

How it works

We convert your annual return during the payout phase into an effective monthly rate so we can simulate changes to the account each month.

Starting from your initial balance, we apply monthly interest, then subtract your fixed monthly withdrawal, and repeat this process month by month.

We keep track of how many months it takes until the balance reaches zero or becomes negative, which gives us months until depletion.

We convert that month count into years and remaining months to make the result easier to interpret at a glance.

At the same time, we keep a running total of all interest earned during the payout period so you can see how much of your withdrawals came from growth versus principal.

If the monthly withdrawal is less than or roughly equal to the monthly interest earned, the balance may not deplete within a reasonable time—monthsLasted may be null in that edge case to indicate a potentially sustainable payout.

Formula

We simulate month by month using a simple compound-interest-with-withdrawals model.\nMonthly rate r = (1 + Annual return)^(1/12) − 1\nEach month: interest = current balance × r; new balance = current balance + interest − monthly withdrawal.\nWe repeat until the balance ≤ 0, counting months, then convert to years and months and sum all interest along the way.

When to use it

Checking whether a planned monthly withdrawal amount appears sustainable over the retirement horizon you care about given your current balance and return assumption.
Comparing different withdrawal amounts or investment return scenarios to see how they change the payout duration.
Experimenting with higher or lower withdrawal rates to understand how quickly your balance could be depleted if markets underperform.
Using as a quick gut check before exploring more complex, tax-aware retirement decumulation strategies with a planner or advisor.
Testing what happens if you temporarily increase withdrawals for a few years (for example, to pay off a mortgage) and then reduce them later, by running multiple scenarios.

Tips & cautions

Use conservative return assumptions, especially if you are already retired or close to retirement; overestimating returns can make a plan look safer than it really is.
Try modeling a lower withdrawal amount than you think you need to see how much extra safety margin it provides in terms of years of coverage.
If monthsLasted is null or extremely large, your withdrawal may be close to or below the account’s expected interest—consider that a sign of a potentially sustainable payout, but still stress-test with lower returns.
Revisit this calculator regularly as market conditions, balances, and spending needs change, rather than relying on a one-time projection.
Use this in combination with Social Security, pensions, and other income sources to build a complete picture of retirement cash flow.
Simplified straight-line model; it ignores taxes, fees, required minimum distributions, and the timing of different income sources.
Assumes constant monthly withdrawals and a constant average return; in reality, you may adjust spending over time and markets are volatile (sequence-of-returns risk).
Does not incorporate inflation or cost-of-living adjustments, so all figures are in nominal dollars.
Does not differentiate between account types (taxable, traditional, Roth), which can have very different after-tax outcomes.
Not a substitute for a full retirement plan that includes longevity risk, health care costs, and contingency plans for bad market stretches.

Worked examples

500k balance, 4% return, $2,500 monthly

Set retirement balance to $500,000, annual return to 4%, and monthly withdrawal to $2,500.
The calculator simulates monthly growth and withdrawals until the balance is depleted.
You might see a payout duration on the order of a couple of decades, with total interest showing how much growth helped support your withdrawals.
Interpretation: if this horizon is shorter than you want, you may need to lower withdrawals, work longer, or accept more investment risk (with care).

Comparing $2,000 vs $3,000 monthly withdrawals

Run the calculator first with a $2,000 monthly withdrawal and note the years and months the balance lasts.
Then run it again with a $3,000 monthly withdrawal, leaving balance and return assumptions unchanged.
Compare the payout durations to see how increasing monthly withdrawals shortens the life of the portfolio.

Lowering return assumptions to be conservative

Start with an optimistic annual return (for example, 6%) and run the calculator with your planned monthly withdrawal.
Then reduce the annual return to a more conservative figure (for example, 3–4%) and run it again.
Interpretation: use the lower-return scenario as a stress test for your plan; if you still get a comfortable payout duration, your plan may be more robust.

Deep dive

See how long your retirement balance might last with a fixed monthly withdrawal and an assumed investment return, and how much interest you could earn along the way.

Enter your balance, expected annual return during retirement, and monthly withdrawal to estimate payout duration in years and months.

Helpful for retirees and pre-retirees who want a quick, numbers-based view of how different withdrawal levels affect the longevity of their savings.

FAQs

Does this calculator model inflation or cost-of-living adjustments?: No. All figures are in nominal dollars with a fixed monthly withdrawal. To approximate inflation, you can either reduce your withdrawal target to leave a safety margin or run separate scenarios with increasing withdrawals over time.
How should I choose the annual return during payout?: Use an estimate that reflects your actual asset allocation and risk tolerance, but err on the conservative side—especially in retirement, where large early losses can hurt sustainability. Many planners test scenarios in the 3–5% range for diversified portfolios.
What does it mean if monthsLasted is blank or extremely large?: That usually means your monthly withdrawal is at or below the expected monthly interest, so the balance does not deplete in the simulation horizon. While that suggests a potentially sustainable payout, real-world volatility and inflation still matter, so you should treat it as a hopeful sign, not a guarantee.
Can I use this instead of a full retirement plan?: No. This is a quick, high-level tool to understand how withdrawal levels interact with balances and returns. A full plan should consider taxes, Social Security, pensions, other accounts, and detailed cash-flow projections.

Related calculators

finance

Retirement Payout Calculator

Calculate a fixed monthly payout from a retirement balance over a set number of years with an assumed annual return, plus total paid and interest portion.

finance

Retire with Social Security + Pension

Combine pension income, Social Security, and a withdrawal rate on savings to see total annual retirement income.

finance

Updated Retirement Calculator

Project retirement savings growth with contributions, then combine a withdrawal rate with pension and Social Security to estimate annual retirement income.

This retirement payout duration calculator is an educational tool that models a simplified withdrawal schedule with constant returns and fixed monthly withdrawals. It does not account for taxes, inflation, market volatility, or individualized financial circumstances and should not be used as the sole basis for retirement decisions. Consult a qualified financial planner or tax professional before making changes to your withdrawal strategy.