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Show formula & working
Each path: every year's return = average + volatility × a random normal draw (seeded). Before retirement: balance × (1 + r) + that year's SIP; after: (balance − inflation-rising withdrawal) × (1 + r)
Chance money lasts = paths that never run out before the planning age ÷ all paths; bands = 10th, 50th and 90th percentile of the balance each year
How this works
A plan built on one average return hides the risk of bad years — especially bad years just after retirement. Monte Carlo runs the plan through thousands of random return sequences.
The chance your money lasts is the share of paths that never run dry. Because returns vary, the typical (median) path grows more slowly than the average return suggests.
The same seed always gives the same result, so you can compare changes fairly.
Frequently asked questions
What is a good success rate?
Many planners aim for 80% or more. Below that, consider saving more, retiring later or spending less.
Why is the median below the plan's projection?
Volatility drags down compound growth: a 10% fall followed by a 10% rise leaves you below where you started.
Are the returns realistic?
They are illustrative assumptions with a simple normal distribution; real markets have fatter tails.
How many paths should I run?
2,000 is usually enough for a stable answer; 5,000 gives a little more precision.
Want a second opinion on your plan?
Talk to Rytvae about the assumptions behind your retirement numbers.