RandRoute · South African money tools
Compound Interest Calculator
See the difference between what you put in and what growth could add.
Calculator inputs
- Starting amount
- Monthly contribution
- Annual return assumption
- Time invested
How the calculator works
The compound interest estimate grows a starting balance and regular monthly contributions at a chosen annual return assumption, then separates contributions from growth.
Example calculation
Enter R20,000 as a starting balance and add R2,000 a month for ten years. Compare the projected contributions with the possible growth, then test a lower return assumption.
Frequently asked questions
- What is compound interest?
- Compound growth means returns can earn further returns. The longer the time horizon and the more consistent the contributions, the more meaningful the effect can become.
- Is the projected return guaranteed?
- No. The rate is an assumption for planning. Actual investment returns vary and may be negative over some periods.
Related financial tools
Estimate only. Results are based on the information entered and applicable assumptions. Actual amounts may differ.