What is a retirement income calculator?
A retirement income calculator estimates how long a remaining balance may support a monthly withdrawal at a return rate you enter. This NumberMotive version also shows months of income, a projected depletion month, the starting balance used, the withdrawal amount and how much modeled growth contributed to those withdrawals.
The result is an educational estimate from the numbers you type. It is not financial advice, investment advice, professional retirement planning, a recommendation to withdraw a specific amount, a guarantee that savings will last or an official Social Security calculation.
How retirement income is modeled here
The model applies a constant monthly return, then a constant monthly withdrawal, until the balance reaches $0.00 or the withdrawal no longer reduces the balance. Extra contributions, changing withdrawals and market paths are not modeled.
The annual return is a number you enter. It is converted to a monthly rate by dividing by 12. That conversion is a planning convention, not a guaranteed yield, a market forecast or a Social Security formula.
The formulas this calculator uses
Monthly rate r = expected annual return ÷ 100 ÷ 12
Each month: remaining balance = remaining balance × (1 + r). Then subtract the monthly withdrawal, or the remaining balance if that is smaller.
When r is 0%, no growth is added and the balance falls by the withdrawal each month. When the balance is $0.00, income is already depleted. When the withdrawal is $0.00, or when the withdrawal does not exceed that month’s modeled return, the balance does not fall. The calculator does not return NaN or Infinity.
Growth contribution is total modeled withdrawals minus the starting balance, not below $0.00. It is not estimated when a depletion cannot be calculated.
Worked example
With a $500,000.00 balance, a $2,000.00 monthly withdrawal and a 4% annual return, the first month’s modeled return is $1,666.67. The withdrawal is larger, so the balance declines. The estimated duration is 539 months (44 years 11 months). Total modeled withdrawals are $1,076,847.26. Growth contribution is $576,847.26.
Lowering the withdrawal to $1,500.00 keeps it at or below the first month’s return, so a depletion is not estimated. A 0% return with the $2,000.00 withdrawal lasts 250 months. None of those inputs is a recommended withdrawal plan.
What this calculator does not include
- Social Security, pensions or employer-plan rules
- Inflation, taxes, required minimum distributions or sequence-of-returns risk
- Investment advice, portfolio allocation or a guaranteed return
- A recommendation of how much to withdraw
- A professional retirement-income plan
Limitations of this calculator
- Results are estimates based only on the balance, withdrawal and return you enter.
- The schedule assumes a constant monthly return and a constant withdrawal.
- A withdrawal that does not reduce the balance does not produce an infinite duration.
- A path that would last more than 1,201 modeled months is not treated as a finite depletion.
- The depletion date is a calendar label from today’s UTC month plus the estimated months. It is not a benefit payment date.
- Scenarios are not saved, emailed or sent to analytics.
Frequently asked questions
What is a retirement income calculator?
It estimates how long a remaining balance may support a monthly withdrawal at a return rate you enter. This NumberMotive version also shows months of income, a projected depletion month, the starting balance, the withdrawal amount and modeled growth. It is an educational worksheet, not a retirement-income plan.
How is estimated years of income calculated?
Each modeled month applies a monthly return, then subtracts the withdrawal. Months are counted until the balance reaches $0.00. With $500,000.00, $2,000.00 a month and a 4% return, the estimate is 539 months, shown as 44 years 11 months.
What expected annual return should I enter?
Enter the annual percentage you want to model. The calculator does not look up market returns, recommend an allocation or convert a historical average. 4% is the default. 0% is valid and treats later withdrawals as coming from principal only.
Is the expected return a guaranteed return or a market forecast?
No. The field is a planning assumption you type. Dividing by 12 is a monthly-model convention. It is not a guaranteed yield, a forecast of future markets or an official benefit rate.
What if the monthly withdrawal is $0?
A $0.00 withdrawal is valid. The balance is not reduced, so a depletion is not estimated. The calculator does not return Infinity or keep looping.
What if the retirement balance is $0?
A $0.00 balance is treated as already depleted. Estimated years, months, total withdrawals and growth contribution are 0 and $0.00.
What if the expected annual return is 0%?
A 0% return is valid. No growth is added. The balance falls by the withdrawal each month. Growth contribution is $0.00 when a depletion can be calculated. On $500,000.00 with a $2,000.00 withdrawal, the estimate is 250 months.
What if the withdrawal is larger than the monthly return?
The remaining balance declines. Months are counted until $0.00. On $500,000.00 at 4%, $2,000.00 is above the first month’s $1,666.67 modeled return, so the worksheet shows a finite duration.
What if the withdrawal is smaller than the monthly return?
The modeled balance does not fall. A depletion is not estimated and Infinity is not returned. On $500,000.00 at 4%, $1,500.00 is below the first month’s modeled return.
How is growth contribution calculated?
It is total modeled withdrawals minus the starting balance, not below $0.00. With the $500,000.00 / $2,000.00 / 4% example, growth contribution is $576,847.26. It is not estimated when a depletion cannot be calculated.
How is the projected depletion date calculated?
When a month count is estimated, the worksheet adds that many months to the current UTC month and shows the resulting month and year. It is a calendar label, not a benefit payment date.
Does this include Social Security, pensions or employer plans?
No. Those sources are outside this worksheet. The estimate uses only the balance, withdrawal and return you type.
Does this include inflation or taxes?
No. The model uses a constant withdrawal and a constant monthly return. It does not adjust for inflation, taxes, required minimum distributions or changing prices.
Is this a recommended withdrawal amount?
No. The monthly withdrawal is a number you enter for comparison. The calculator does not recommend a withdrawal, a spending rate or a 4% rule.
Can this guarantee that retirement savings will last?
No. The duration is an educational estimate from a constant return and a constant withdrawal. Markets, spending and longevity can differ. It is not a guarantee of sustainability.
Is this result financial advice or official retirement planning?
No. It is an educational estimate from a balance, withdrawal and return you chose. It is not financial advice, investment advice, professional retirement planning, a withdrawal recommendation or an official Social Security calculation.
Last reviewed August 25, 2026 (UTC).