semkuHow long will the money last calculator
Enter a balance, monthly withdrawal and annual assumptions to estimate how many full withdrawals the balance covers.
Annual assumptions
Show all yearly balances
| Year | Month | Balance after withdrawal (USD) | Monthly withdrawal for that year (USD) |
|---|---|---|---|
| 1 | 12 | $91,781.56 | $1,000.00 |
| 2 | 24 | $82,990.01 | $1,020.00 |
| 3 | 36 | $73,597.54 | $1,040.40 |
| 4 | 48 | $63,575.14 | $1,061.21 |
| 5 | 60 | $52,892.51 | $1,082.43 |
| 6 | 72 | $41,518.06 | $1,104.08 |
| 7 | 84 | $29,418.83 | $1,126.16 |
| 8 | 96 | $16,560.44 | $1,148.69 |
| 9 | 108 | $2,907.00 | $1,171.66 |
Month 111 — final partial withdrawal: $533.71 paid of $1,195.09 required; balance after withdrawal: $0.00.
Amounts are shown in USD to the nearest cent, with ties rounded away from zero; displayed amounts are not reused in the calculation.
Sources
NIST — Handbook 135: Life Cycle Costing Manual for the Federal Energy Management Program
Provides uniform present value formulas for equal end-of-year amounts and for a series increasing at a constant rate. This calculator applies the same algebra to monthly periods as its own model choice.
IRS — Substantially equal periodic payments FAQ
The fixed amortization example divides an account balance by the present value factor for $1 paid at each year-end to determine equal annual withdrawals. This calculator works in reverse, counting how many scheduled withdrawals can be paid in full under your assumptions.
Section 3.01(b) defines the annual payment as the amount that results in level amortization of the account balance over a specified number of years.
Provides the general annual percentage yield (APY) formula, which annualizes interest earned over a term using an exponent. This calculator derives its monthly growth rate by reversing that annualization structure.
U.S. Securities and Exchange Commission, Investor.gov — Compound Interest Calculator
Accepts a negative monthly contribution for an amount withdrawn from the principal each month.
U.S. Securities and Exchange Commission, Investor.gov — Managing Lifetime Income
Discusses savings lasting through retirement and longevity risk, the risk of outliving your assets.
Calculation rules
This calculator defines each withdrawal as occurring at the end of the month, after growth is applied to the balance, with the first withdrawal one month from now.
This calculator derives the monthly growth rate by reversing the annualization structure of the APY formula in Regulation DD Appendix A: it takes the twelfth root of one plus the effective annual return, then subtracts one, rather than dividing the annual rate by 12.
This calculator defines the withdrawal increase as an annual step, starting with withdrawals 13, 25, 37 and onward; the increase is not compounded each month.
This calculator defines its rounding rule as retaining internal precision between withdrawals and rounding only displayed amounts to cents, with ties rounded away from zero.
This calculator defines its calculation limit as 1,200 months (100 years); an undepleted balance at that point does not describe what happens beyond the calculation limit.
Taxes, fees, changing returns, the order of returns and incoming income are excluded from this arithmetic model with fixed assumptions.
This calculator defines a partial withdrawal as separate from the count of full withdrawals; a final full withdrawal that leaves exactly zero is included in that count.
This calculator defines P as the starting balance, W_0 as the first-year monthly withdrawal, a as the effective annual return and f as the annual withdrawal increase, with both rates expressed as decimals. B_0=P; i=(1+a)^(1/12)−1; W_k=W_0(1+f)^floor((k−1)/12); A_k=B_(k−1)(1+i); payment_k=min(W_k,A_k); B_k=max(0,A_k−W_k). For months k=1 through 1,200, growth precedes withdrawal. Stop at the first partial withdrawal or exact depletion; a zero starting balance covers zero full withdrawals. Total withdrawn is the sum of payments, including the final partial payment when present.
Frequently asked questions
- Why is the partial withdrawal separate from the full withdrawal duration?
- The duration counts months in which the entire scheduled amount is paid. In the example, 110 months are paid in full; month 111 requires $1,195.09, but only $533.71 is available. An exact final full withdrawal is counted even when it leaves a zero balance.
- When does the withdrawal amount increase?
- The first-year monthly amount applies to withdrawals 1 through 12. The annual increase first applies at withdrawal 13, then again at withdrawals 25, 37 and onward. It is your inflation assumption, not a measured inflation rate.
- What does effective annual return mean here?
- It is the assumed growth over a full year including compounding. This model uses the monthly rate (1+a)^(1/12)−1, where a is the annual rate as a decimal, and applies growth before each month-end withdrawal.
- Can I enter zero withdrawals or a negative return?
- Yes. Zero withdrawals and a zero return leave a positive starting balance undepleted within the calculation limit. Negative annual returns greater than −100% are accepted, and a zero starting balance covers zero full withdrawals.
- What happens at the calculation limit?
- The calculation covers at most 1,200 months, or 100 years. If the balance has not been depleted, the result gives the remaining balance at that point and makes no estimate beyond it.
- Why can the actual withdrawal duration differ?
- This model holds your return and annual increase assumptions constant. Changes in returns, their order and your actual withdrawals can change the duration; the result describes only the entered scenario.
Compound interest calculator — Estimate growth with contributions rather than a withdrawal duration.
Savings account calculator — Estimate a savings balance or contributions toward a goal rather than a withdrawal duration.
Privacy on this page
Calculations run in your browser. When you change the inputs, the balance, withdrawal amount, effective annual return and annual withdrawal increase are stored after # in the page URL. Sharing that link also shares those values. The fragment is not sent with the page request. Calculation inputs and results are not sent to the server or saved in browser storage; the URL can remain in browser history or bookmarks.
To understand how the page is used and to improve the service, this page sends semku’s own usage statistics and automatic error reports. They go only to the dedicated endpoint under semku.com/api/telemetry/v1/. They are not used for advertising or third-party tracking.
The usage statistics include stages of use (such as starting an operation or requesting a copy), the times they occur and fixed identifiers that distinguish the page and feature. They do not include the balances, withdrawal amounts, return rates or annual increase rates you enter, the durations, yearly balance tables or other results shown, or the text you copy. Inputs are not sent as hashes or as size categories either. The full URL and search terms are not sent.
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Calculations run in your browser without sending your calculation inputs or results to the server.