Compound growth calculator: what regular contributions actually become

Compounding is described so often that it stops meaning anything. The useful version is a single comparison: how much of the final number is money you put in, and how much appeared on its own. Early on, almost all of it is yours. The point at which that flips is the thing worth seeing.

How to read the result

The headline balance matters less than the split beneath it. If growth is a small fraction of the total, the outcome is being driven by your contributions, not by returns — which means the lever that actually moves it is saving more, not chasing a higher rate.

Common mistakes

• Using a return rate nobody could sustain. A percentage point of optimism compounds into a large error over twenty years.
• Forgetting fees. A 1% annual fee is roughly a 1% lower return, every year, and it compounds against you exactly as returns compound for you.
• Ignoring inflation. This shows nominal money; what it buys in twenty years is meaningfully less.
• Treating a smooth curve as a promise. Real returns arrive unevenly, and a bad first few years hurts far more than a bad final few.

What this does not include

• Tax on gains or contributions
• Platform, fund or advice fees
• Inflation
• Any year in which the return is negative