Deterministic retirement plannerRetirement Monte Carlo Planner
One retirement.
10 000 possible futures.
See the probability—not just the average. Model investment uncertainty, changing spending, sequence risk and household longevity.
01 Define the income02 Model uncertainty03 Measure resilience
01
Your starting point
Turn a drawdown percentage into an income promise.
The initial rand income is set once and then increased through retirement. This lets the model identify income pressure—rather than declaring success merely because a small capital balance remains.
Starting gross income from capitalR 16 667 / month
R 200 000 in year one = R 5 000 000 × 4%
02
Investment uncertainty
An average return is only the centre of the story.
Choose an illustrative portfolio profile or enter your own expected nominal return after fees and annual standard deviation. The profiles are planning assumptions—not forecasts or asset-allocation advice.
03
Spending through retirement
Retirement spending need not follow one straight line.
Income increases with inflation, while optional phases model a retirement spending smile. Spending slows in the middle years and returns to 100% by default in later life.
Income response strategy
Choose how income responds when markets disappoint.
The flexible options may improve capital survival by accepting less income in some simulated paths. The results show both the probability benefit and the lifestyle cost.
The model pays income monthly at the beginning of each month and then applies that month’s investment growth.
04
Longevity and household survival
Financial survival and human survival answer different questions.
Mortality probabilities use the published South African Annuitant Standard Mortality Tables: SAIML98 for males and SAIFL98 for females. They are group planning averages—not personalised lifespan predictions.
Your modelled result
The income plan is vulnerable
Fewer than 60% of the simulated paths maintain the intended income to the selected planning age.
Income success to age 10050,1%10 000 deterministic-seed simulations
98%
Age 80
Probability of maintaining the selected income strategy
100% still have capital—but capital alone does not prove the income is adequate.91%
Age 85
Probability of maintaining the selected income strategy
100% still have capital—but capital alone does not prove the income is adequate.76%
Age 90
Probability of maintaining the selected income strategy
100% still have capital—but capital alone does not prove the income is adequate.62%
Age 95
Probability of maintaining the selected income strategy
100% still have capital—but capital alone does not prove the income is adequate.50%
Age 100
Probability of maintaining the selected income strategy
100% still have capital—but capital alone does not prove the income is adequate.Median capital at age 100 · future nominal randR 7 665 378
10th-percentile capital · future nominal randR 593 486
Median shortfall age among failed pathsAge 90
Planned income lasts for client / last survivor85,9%
05
The thousands-of-futures view
Your retirement follows one path. Today, nobody knows which one.
The fine lines are a sample of 140 simulated paths. The shaded fan summarises all 10 000 paths, while the dark line is the median—not a forecast.
Sample paths10th–90th percentile25th–75th percentileMedian
All capital amounts are future nominal rand: the rand amount expected in that future year, without converting it back to today’s purchasing power. Income success measures whether the selected income strategy remains payable, including the selected living-annuity limit.
| Age | Income success | 10th percentile future nominal rand | Median capital future nominal rand | 90th percentile future nominal rand |
|---|---|---|---|---|
| 80 | 98,3% | R 3 998 986 | R 8 920 304 | R 17 378 123 |
| 85 | 91,3% | R 2 979 979 | R 10 591 479 | R 24 660 242 |
| 90 | 75,9% | R 1 711 805 | R 11 134 642 | R 34 606 869 |
| 95 | 61,8% | R 1 003 558 | R 10 556 751 | R 47 876 659 |
| 100 | 50,1% | R 593 486 | R 7 665 378 | R 65 263 414 |
06
Sequence-of-return risk
The same returns. A radically different retirement.
The orange and green paths use the same set of returns: losses arrive early or late. The dashed line adds the model's median capital at each age as a reference. Withdrawals make the order matter.
Losses arrive earlyMonte Carlo median capitalLosses arrive late
The dashed line is the median capital across all simulated portfolios at each age. It is not one single actual portfolio journey: the portfolio in the middle can change from age to age, and it does not use the illustrative five-year return set.
07
Mortality and last-survivor view
How likely is the household to still need the income?
The probabilities are measured at the same future dates. If a spouse is younger, their displayed age is therefore lower than the client’s age.
Client median modelled lifetimeAge 8450% modelled probability of living beyond approximately this age
Client prudent planning ageAge 97Approximately 10% modelled probability of living beyond this age
Probability the planned income lasts for the client’s or last survivor’s modelled lifetime85,9%
Median capital at the last death · future nominal randR 7 505 272
Each combined simulation generates an investment path and a modelled lifetime. A single-client run ends at the client’s death; a couple’s run ends at the second death. “Success” means the selected income strategy remains payable while at least one person is alive. Spending changes to 75% after the first death when a spouse is included.
08
How the estimate works
Transparent assumptions, not false precision.
The calculator is designed to make uncertainty visible. Changing the assumptions should change the answer—and no probability is a guarantee.
Annual nominal returns after fees are generated from a lognormal model calibrated to the entered arithmetic return and standard deviation. Returns cannot fall below −100%.
Year-one income equals capital × drawdown and is paid monthly at the beginning of each month. The benchmark follows inflation and spending phases; optional rules may pause increases or apply guardrails path by path.
A path succeeds while the selected income strategy remains payable. With the living-annuity limit selected, exceeding 17.5% counts as an income failure before capital reaches zero.
The model uses the published SAIML98 male and SAIFL98 female annual death probabilities for ages 40–110, based on South African immediate-annuitant experience in 1996–2000. The entered longevity margin and mortality improvement are explicit planning overlays, not part of the original tables.
Client and spouse mortality are treated as independent. Investment returns are independent from year to year and from mortality. Real markets and household lifetimes may behave differently.
The model uses a fixed random seed. The same inputs reproduce the same result, making scenario comparisons meaningful instead of changing because the sample changed.
Important: This is an educational stochastic illustration, not a prediction, guarantee or financial, investment, tax, medical or actuarial opinion for a particular person. Portfolio presets are illustrative and not prescribed South African capital-market assumptions. The return model does not fully represent fees that change, tax, market regimes, serial correlation, currency effects, extreme-event clustering or all spending shocks. SAIML98 and SAIFL98 reflect historic group experience and may not represent current or individual mortality; the planning overlays are assumptions, not forecasts. Adaptive-income rules improve modelled success only by accepting lower income in some paths. Review living-annuity income and investments with an appropriately authorised adviser. See the ASISA Living Annuity Standard and the South African Annuitant Standard Mortality Tables.