Systematic Withdrawal Plan Calculator
Model a lump sum that earns a return while you withdraw a fixed amount each month; see the ending balance and total withdrawn after a number of years, for retirement or passive cash flow.
Input Data
Results
At a glance:An SWP pays a fixed amount from a portfolio that keeps earning. Each month: balance = balance × (1 + monthly rate) − withdrawal. After the years, the ending balance and total withdrawn are reported. It suits retirement or passive-income planning.
Formula
Monthly rate = annual return% ÷ 1200.
Each month: balance = balance × (1 + monthly rate) − withdrawal.
Ending balance and total withdrawn reported after the years.
$$B_{t} = B_{t-1} \\times \\left(1 + \\dfrac{r}{12}\\right) - W$$How to Use
- Enter the initial principal.
- Enter the annual return, monthly withdrawal and years.
- Read the ending balance and total withdrawn.
FAQ
What is a Systematic Withdrawal Plan (SWP) and how is it different from a lump-sum investment?
An SWP is an arrangement where you place a lump sum in a portfolio that keeps earning a return, while taking out a fixed amount (usually monthly) on a regular basis. Its typical use is to convert accumulated savings into a steady retirement cash flow: instead of cashing everything out, you keep it invested and draw a portion each month. It differs from a lump-sum investment, where you invest and never withdraw, letting it compound untouched; and from 'interest-only' spending, where principal is untouched. With an SWP, if your withdrawal is below the return, the principal can keep growing, while if it exceeds the return, the principal is gradually eroded and may eventually run out. It is also the opposite of a regular savings plan (SIP), which adds money rather than taking it out.
Why can the principal still grow even after so many withdrawals?
This is counter-intuitive but important. With the default inputs—principal HK$1,000,000, 8% annual return, HK$8,000 monthly for 10 years—you withdraw 8,000 × 120 = HK$960,000 (almost the initial sum), yet the ending balance is still about HK$756,072. The reason is that the return grows faster than the withdrawals: 8% on HK$1m produces roughly HK$80,000 a year in returns while you withdraw HK$96,000, and because the portfolio keeps compounding, the principal net-grows. As long as each period's withdrawal is below the return it generates, the principal grows; only when withdrawals persistently exceed returns is the principal eroded. This is the core trade-off in retirement planning: the withdrawal rate relative to expected return determines how long your money lasts.
What risks and limitations should I know when planning withdrawals with this calculator?
This calculator uses a fixed annual return with stable monthly compounding, which is clear but hides real-world risks. The key one is sequence-of-returns risk: real returns fluctuate, and a market downturn early in the withdrawal period forces you to sell more units at low prices, permanently damaging the principal—so the balance can deplete far faster than a fixed-return model suggests. Inflation also erodes the purchasing power of a fixed withdrawal; taxes and fees reduce the net return below the nominal rate; and results are very sensitive to the return assumption, so use conservative figures and test multiple scenarios. The calculator stops (balance to zero) once funds are insufficient. It is useful for understanding the mechanics, not a guarantee of retirement income—consult a licensed adviser.
What is sequence-of-returns risk and why is it especially deadly for an SWP?
Sequence-of-returns risk means that for a portfolio you are both withdrawing from and investing in, the order in which returns arrive matters enormously—even if the long-run average return is identical. Two retirees with the same HK$1m, same monthly withdrawal and same 20-year average return but reversed sequences can end up with very different balances: the one who hits a downturn early may run out, while the one who starts with gains survives. Early losses force larger proportional sales at low prices, permanently shrinking the base that later compounding relies on. This is deadly for an SWP because withdrawals are rigid—you must take income every month and cannot simply 'wait for a rebound' as a pure investor would. This calculator cannot model that volatility; in practice, use conservative return assumptions, keep a cash buffer, and consider reducing withdrawals in bad markets.
How is an SWP different from SIP (regular savings) and a lump-sum investment?
The three differ in cash-flow direction and life stage. An SWP is a decumulation tool—you already have a lump sum and draw from it, typically in retirement. An SIP (regular savings / monthly contribution) is the opposite accumulation tool—you add money each period and let compounding build wealth, ideal during your working years, with the benefit of dollar-cost averaging. A lump-sum investment is a one-off deposit left untouched to compound. In short: SIP fills the bucket, a lump sum fills it once and lets it settle, and an SWP scoops from the filled bucket while it slowly refills itself with returns. The ideal path is to accumulate with SIP/lump sum while working, then decumulate with an SWP in retirement.
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References
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.