Compound Interest Calculator
Project portfolio growth with monthly contributions — Bear / Base / Bull scenarios across any time horizon
Inputs
$
$
%
yr
Final Balance
$691,150
Base case (7% return)
Total Contributed
$190,000
$10,000 + $6,000/yr × 30
Total Interest Earned
$501,150
263.76% of contributions
Bear vs Bull Spread
$948,458
4% vs 10% — return matters
Portfolio Growth — Bear / Base / Bull
4% · 7% · 10%Bear / Bull lines hold contributions and time constant but shift the annual return by ±3 percentage points. The dashed line is what you'd have if money never grew at all (just contributions).
| Year | Start Balance | Contributed | Interest | End Balance |
|---|---|---|---|---|
| Y0 | $10,000 | — | — | $10,000 |
| Y26 | $462,290 | $6,000 | $33,615 | $501,905 |
| Y27 | $501,905 | $6,000 | $36,479 | $544,384 |
| Y28 | $544,384 | $6,000 | $39,550 | $589,934 |
| Y29 | $589,934 | $6,000 | $42,843 | $638,777 |
| Y30 | $638,777 | $6,000 | $46,374 | $691,150 |