Growth path modeller

Compounding Returns Calculator

Model smooth compounding, variable monthly returns, contributions, withdrawals, percentile outcomes, and drawdowns. Because the spreadsheet path is always much better behaved than the real one.

Smooth ending balance $179,585 +79.6% total return
$176,421median ending ?
$104,213p10 ending ?
$298,880p90 ending ?
28.4%p95 max drawdown ?

Readout

Smooth path looks tidy. Simulated path is less polite.

Risk check

Watch the left tail and drawdown estimate before falling in love with the ending balance.

Generated monthly returns ?

Compounding impact path ?

Ending balance distribution ?

Month-by-month compounding impact

Fully compounded

How to use it

  1. Start with the smooth monthly return to see the idealised growth path.
  2. Add monthly volatility to see a more realistic range of outcomes.
  3. Use contributions or withdrawals to model adding capital or taking profits.
  4. Use the same monthly return sequence across compounding models to see how negative months change the path.
  5. Compare the median, p10, p90, and drawdown numbers before trusting the pretty curve.