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Module C · Saving & Investing Basics · Free

How compounding actually adds up

Time in the market does more work than most people expect — see it with your own numbers below.

The idea in one line

When growth is left in place, it starts earning its own growth — a balance that grows 5% doesn't just add 5% of the original amount each year, it adds 5% of whatever it's grown to. Over enough years, that compounding effect does more of the work than the money you actually put in.

Why starting early matters more than starting big

The same total contribution, spread over more years, usually ends up larger than a bigger contribution spread over fewer years — because the earlier dollars had more time to compound. This is why "start now, even small" is common advice-adjacent framing you'll hear everywhere; the arithmetic below shows why, without telling you what to actually invest in.

See it with your own numbers

● Not saved anywhere

This is the exact same calculator built into the app's Learn & Tools sections — it works identically here, offline, with no account needed. Try more calculators →

What this is not: this shows the arithmetic of compounding at a steady assumed return — real returns vary year to year and aren't guaranteed. It isn't advice about what to invest in or how much risk to take; those depend on your situation.