Albert Einstein supposedly called compounding the eighth wonder of the world. Whether or not he did, the idea is real: your returns start earning returns of their own, and the effect snowballs.
How compounding works
When you earn a return and leave it invested, next year's return is calculated on the larger amount. Do that for many years and growth accelerates — slowly at first, then dramatically.
| Years invested | $1,000 at 8% a year |
|---|---|
| 10 years | ~$2,160 |
| 20 years | ~$4,660 |
| 30 years | ~$10,060 |
The key insight: notice how the jump from year 20 to year 30 is far bigger than from year 0 to year 10. Most of the reward arrives in the later years — which is exactly why starting early beats trying to be clever later.
Two beginner habits that harness it
- Invest regularly (dollar-cost averaging). Putting in a fixed amount on a schedule — say monthly — means you automatically buy more when prices are low and less when they're high, and you never have to guess the perfect moment.
- Stay invested. Compounding only works if you leave it alone. Jumping in and out interrupts the snowball and often means missing the market's best days.
Let profits compound inside the business too
The same idea works for companies. A business that reinvests its profits at a high return on invested capital (ROIC) compounds its own value year after year — and reinvesting your dividends does the same for your portfolio.
Takeaway: time in the market, plus a steady habit, usually matters more than picking the perfect stock. Compounding rewards patience.
