Portfolio Outcome Simulator
A single projected number hides risk. This shows a pessimistic, median and optimistic path for the same plan.
Range of Outcomes
Frequently Asked Questions
Why show three numbers instead of one?
A single projection implies certainty that does not exist. Two portfolios can share the same expected return while one swings far more widely. The 10th and 90th percentile bands make that risk visible.
What does the median actually mean?
Half of comparable outcomes land above it and half below. It sits below the simple compound-growth figure because volatility drags realised returns below the average - the more volatile the portfolio, the bigger that gap.
Which volatility number should I enter?
A globally diversified equity fund has historically run near 15%. A balanced 60/40 mix is closer to 9-10%, and a single stock can exceed 35%. Raising volatility widens the band without improving the median.
Why is the inflation-adjusted figure so much lower?
At 2.5% inflation, money loses roughly 40% of its purchasing power over 20 years. Planning in nominal terms consistently overstates what a portfolio will actually buy.
Worked Examples
The volatility drag
$50,000 plus $500 a month at 7% for 20 years projects about $460,000 on a straight compound basis. Adding 15% volatility pulls the median down and opens a band roughly 2.5x wide from pessimistic to optimistic - same plan, very different lived experience.
Why time matters more than timing
Extending the horizon from 10 to 20 years multiplies contributions by two but the median outcome by considerably more, because early contributions compound the longest.
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⚠️ Disclaimer
A lognormal approximation for education, not a Monte Carlo engine or a forecast. Real markets show fat tails and sequence risk that simple models understate.