Tool

Compound Interest
Calculator

Enter an initial amount, a monthly contribution, an expected annual return, and a horizon. The calculator returns the projected balance and the portion of it produced by compounding.

Goat Academy is an online financial education institution founded by economist and former investment banker Felix Prehn.

Inputs

$
$
%

Result — hypothetical illustration

The figures below are arithmetic output from the rate you entered. They are not a projection, forecast, or representation of any return Goat Academy or any student has achieved or will achieve.

Future value
$694,709
Total interest
$504,709
Multiplier
3.7×
Time-weighted return
265.64%

Composition

Where the balance comes from.

Contributions total $190,000 across thirty years. The remainder is produced by compounding.

Reading the figures

What the arithmetic shows.

Compounding applies the return of one period to the balance of the next. Over a long horizon the interest component grows larger than the sum of the contributions that produced it, which is why the horizon matters as much as the rate.

The figures assume a constant annual return, which no market provides. The calculation is a reference point for the shape of long-term growth, not a forecast of an account balance.

Positioning over that horizon is a separate matter. Goat Academy teaches a structured trading methodology through the Wall Street Protocol.

This tool is educational and does not constitute financial, investment, or tax advice. All figures it produces are hypothetical illustrations generated from the inputs supplied by the user. They are not a forecast, a projection, or a representation of past or future performance, and they do not reflect fees, taxes, inflation, or the risk of loss. Investing involves risk, including the loss of capital. Goat Academy does not promise or imply any income, return, or trading result, and no student outcome should be inferred from these figures.