How long will my retirement savings last?
Example: start at age 65 with $500,000, spend $3,500 a month and receive $2,000 a month from Social Security. At a constant 5% return, 0.3% fees and 2.5% inflation, spending is covered through age 100, the end of the model, with $353,864 still left. Change any input below.
With these inputs spending is covered through age 100 (the end of the model), with $353,864 still left.
This is arithmetic on a constant return, not a forecast. Real returns vary year to year; see the order-of-returns example.
With and without the income
| Case | Result |
|---|---|
| With the income above | covered through age 100, $353,864 left |
| Without any income | short by age 80 (14 consecutive full years funded before the first shortfall) |
If inflation is different
Your other inputs stay the same; only the inflation rate changes. Spending and income both rise with it.
| Inflation | Result |
|---|---|
| 2% a year | covered through age 100, $501,529 left |
| 3% a year | covered through age 100, $190,640 left |
| 4% a year | short by age 98 (32 consecutive full years funded before the first shortfall) |
How long does a withdrawal rate last?
Planned first-year spending = the rate times your starting savings, then raised with inflation each year, with no other income. Uses your return, inflation and fees (and the optional tax rate, which makes the gross withdrawal larger than the rate). This is arithmetic on a constant return, not a "safe withdrawal rate".
| Spending rate | Planned first year / month | Result |
|---|---|---|
| 3% | $15,000 / $1,250 | covered through age 100, $710,752 left |
| 4% | $20,000 / $1,667 | covered through age 100, $115,939 left |
| 5% | $25,000 / $2,083 | short by age 93 (27 consecutive full years funded before the first shortfall) |
| 6% | $30,000 / $2,500 | short by age 87 (21 consecutive full years funded before the first shortfall) |
Balance by age
The table below lists the same year-end balances for the "with income" line.
| Age at year end | Growth | Planned spending | Income | Tax needed | Balance |
|---|---|---|---|---|---|
| 66 | $23,500 | $42,000 | $24,000 | $0 | $505,500 |
| 67 | $23,759 | $43,050 | $24,600 | $0 | $510,809 |
| 68 | $24,008 | $44,126 | $25,215 | $0 | $515,905 |
| 70 | $24,476 | $46,360 | $26,492 | $0 | $525,376 |
| 75 | $25,415 | $52,452 | $29,973 | $0 | $543,676 |
| 80 | $25,889 | $59,345 | $33,911 | $0 | $551,283 |
| 85 | $25,685 | $67,143 | $38,368 | $0 | $543,410 |
| 90 | $24,525 | $75,966 | $43,409 | $0 | $513,768 |
| 95 | $22,040 | $85,949 | $49,114 | $0 | $454,144 |
| 100 | $17,756 | $97,244 | $55,568 | $0 | $353,864 |
"Planned spending" and "Tax needed" are what the plan calls for. After the money runs short they are still shown but are not fully paid.
What moves the answer most
Table: the age by which the money runs short ("not by 100" means it is still positive at the end of the model, age 100), starting from the example above and changing only monthly spending (rows) and the constant return (columns). Computed with the same model as the calculator.
| Spending / month | 3% return | 4% return | 5% return | 6% return | 7% return |
|---|---|---|---|---|---|
| $3,000 | not by 100 | not by 100 | not by 100 | not by 100 | not by 100 |
| $3,500 | age 95 | age 100 | not by 100 | not by 100 | not by 100 |
| $4,000 | age 87 | age 90 | age 94 | not by 100 | not by 100 |
| $4,500 | age 83 | age 85 | age 87 | age 90 | age 95 |
| $5,000 | age 80 | age 81 | age 83 | age 85 | age 87 |
Reading the table: the gap between spending and benefits drives the result. In the example, benefits cover $2,000 of the $3,500 spending, so savings fund the difference. Without any benefits the same savings run short by age 80; with $1,000,000 and no benefits the result is age 100.
What this does not show
The tool starts from the savings you have when withdrawals begin; growth before that point is not included. A constant return is a simplification. Markets do not deliver the same return every year, and the order of good and bad years matters once you withdraw money. See the same returns in three different orders. Only an optional flat tax percentage that you enter is included; tax rules, account types, required withdrawals, health costs and one-off expenses are not modelled.
Model assumptions
- Annual time steps: the return is applied to the opening balance, then spending is withdrawn and income is added at year end.
- Year 1 uses your amounts as entered; spending and income both rise with the inflation rate from year 2 (income is treated as fully cost-of-living adjusted, including before it starts).
- Fees are subtracted from the return every year.
- The balance cannot go below zero. "Runs short" means that year's spending could not be fully paid, so the balance is zero at year end. Spending that is exactly covered counts as funded.
- Optional tax: one flat percentage you enter, applied only to money taken from savings (spending minus income, grossed up). Income is treated as already after tax. It is a simplification, not a tax calculation.
- Required minimum distributions, account types and one-off costs are not modelled.
- In the savings-duration tool the return is the same every year, so it shows the arithmetic of your inputs, not a forecast. The sequence example instead uses a different return each year.
Educational estimate from the values you enter; not financial advice. Built and reviewed by Hommer Zhao, who is not a licensed financial adviser. See methodology.