Money Basics
Compound Interest, Explained With One Visual
See how starting balance, regular contributions, rate of return, time, and fees can change compounding—without confusing finance jargon.
Time does the heavy lifting
The short version
- Compounding means growth can build on earlier growth.
- Time and consistent contributions can matter as much as the starting amount.
- Returns are not guaranteed, and fees can quietly reduce the amount that keeps compounding.
Compounding is growth on top of earlier growth. In a savings account that may be interest on interest. In an investment, it can be reinvested gains or income generating additional potential growth—with market risk along the way.
Time does the heavy lifting
The five ingredients
| Input | What it changes |
|---|---|
| Starting amount | The first base that can grow |
| Contributions | New money added over time |
| Return | The uncertain rate of gain or loss |
| Time | How long each contribution can participate |
| Fees and taxes | What may leave less money invested |
Read an example correctly
A calculator can show what might happen under a constant assumed rate. That is a scenario, not a prediction. Markets do not deliver the same result every year, and the order of gains and losses matters when money is added or withdrawn.
Run a two-minute experiment
- Open the Investor.gov compound-interest calculator.
- Change only the time period and compare the result.
- Reset, then change only the regular contribution.
- Try a lower assumed return or higher fee to see why conservative inputs matter.
Sources and further reading
- Compound Interest Calculator — Investor.gov
- Financial Tips for New Investors — FINRA
- Introduction to Investing — Investor.gov
Educational content only—not personalized investment, legal, or tax advice. Investing involves risk, including possible loss of principal. Simulated results do not predict real-world performance.