Compound Interest
Usage Tips
Separate your starting principal and regular contributions when planning long-term growth
Compound growth can change a lot depending not only on the return rate, but also on the investment period and the amount you add each month. Enter your starting principal, monthly contribution, expected annual return, and time period to compare the share of principal and earnings, year-by-year asset growth, and long-term saving or investing plans.
What is Compound Interest?
The Compound Interest Calculator estimates future value from principal, return rate, contribution cadence, and investment horizon. It is designed for scenario analysis in long-term accumulation planning.
How to Use
- 1Enter initial principal and periodic contribution amount.
- 2Set annual return rate and compounding frequency (annual, monthly, etc.).
- 3Set investment duration and review projected balance.
- 4Run sensitivity analysis by adjusting return assumptions or time horizon.
Reference Knowledge
- ●Simple interest: A = P(1 + rt).
- ●Compound interest: A = P(1 + r/n)^(nt).
- ●When periodic contributions are included, future value of an annuity is applied.
FAQ
Q.Why does compounding frequency matter?
With the same nominal annual rate, more frequent compounding can increase final value.
Q.Are taxes and fees included?
Baseline calculations are gross unless explicit cost inputs are included.
Q.Can negative return scenarios be modeled?
Yes. Negative rates can be used to test downside outcomes.
Q.How are monthly contributions included?
When monthly contributions are entered, the calculator assumes recurring deposits during the period and includes them in the future-value simulation.