Portfolio by age
Shaded bands show where 50% (dark) and 80% (light) of simulated paths fall. Hover, tap, or use the arrow keys to read a given age. All values are in today's dollars.
Start from a fictional persona
Ending balances
Share of simulations by balance at the plan end age.
When plans fail
Share of all simulations that run out of money at each age.
Sequence-of-returns risk
How the simulation works
- Each year, stock and bond returns are drawn from correlated lognormal distributions (seeded mulberry32 plus Box-Muller), matched to your expected return and volatility, then blended by your stock share and rebalanced annually.
- Everything is in real (today's) dollars. Nominal returns are converted with your inflation rate.
- Before retirement, contributions are added at the end of each year and grow at the rate you set. In retirement, spending is taken at the start of each year.
- A plan succeeds only if every year of spending is paid in full through the plan end age.
- Guardrails hold spending steady, cut it by the adjustment size when the live withdrawal rate climbs above the band, and raise it when the rate falls below.
Educational only. This is a simplified model, not financial advice. See the README for assumptions and limitations.