Withdrawal Sustainability Lab
Set the withdrawal assumptions
Model a fixed nominal withdrawal or a withdrawal that rises with your inflation assumption. The sample values below are placeholders, not recommended returns, spending levels, or withdrawal rates.
Modeled funding range
Seed 1729 · 5,000 paths · 30 years · inflation-adjusted withdrawals
Depletion timing
Conditional on the 2,989 simulated paths that could not fully fund a scheduled withdrawal.
| Percentile | First underfunded withdrawal |
|---|---|
| 10th | Year 14 |
| 25th | Year 16.6 |
| 50th | Year 20.5 |
| 75th | Year 24.7 |
| 90th | Year 27.8 |
Same returns, different order
This five-year illustration takes one seeded set of 60 monthly returns and orders the exact same returns from lower to higher, then from higher to lower. Both orders have the same compounded market return before withdrawals.
This intentionally extreme ordering is an illustration of sequence risk, not a probability estimate or a forecast of how returns will arrive.
Ending balances and withdrawals
Each column shows its own percentile across all simulated paths. Values in the same row are not necessarily from the same path.
| Percentile | Nominal ending balance | Today's-dollar ending balance | Cumulative withdrawals |
|---|---|---|---|
| 10th | $0 | $0 | $921,634 |
| 25th | $0 | $0 | $1,216,971 |
| 50th | $0 | $0 | $1,842,933 |
| 75th | $1,098,562 | $523,732 | $2,195,135 |
| 90th | $3,604,980 | $1,718,648 | $2,195,135 |
How to read this model
The model uses the same seeded monthly lognormal return process as the Portfolio Monte Carlo Lab. Your expected return, volatility, inflation, withdrawal policy, horizon, and seed are assumptions. They are not inferred from a portfolio or treated as forecasts.
A path is counted as funded only while it can pay every scheduled monthly withdrawal in full. If a path cannot fund a scheduled withdrawal, the remaining balance is withdrawn, the portfolio is set to zero, and later withdrawals stop. The model does not assume borrowing.
Fixed nominal withdrawals stay unchanged in dollar terms. Inflation-adjusted withdrawals increase once per year using your inflation assumption. Today's-dollar ending balances use that same inflation rate for purchasing-power context.
These probabilities describe this finite seeded model, not guarantees about retirement outcomes. The tool does not label any withdrawal rate as safe, estimate life expectancy, recommend an allocation, or account for taxes, fees, Social Security, pensions, required distributions, or changing spending needs.