Inputs and options
The Compound Interest Calculator is an input-based calculator — you type values directly in your browser. Nothing is uploaded.
Inputs
| Input | What to enter |
|---|---|
| Principal | The starting amount you deposit or invest |
| Annual interest rate | The yearly rate, e.g. 7% or 12% |
| Time period | The number of years |
| Monthly contribution | A fixed recurring amount added each month (optional) |
Options
- Compounding frequency — annual, quarterly, or monthly; affects how often interest is added to the balance
- Growth chart — a year-by-year view showing the balance climb across the period
- Contribution toggle — turn monthly contributions on or off to see their effect
Getting the best results
- Match the compounding frequency to your actual deposit or loan so the projection is realistic
- Enter the rate as the annual percentage (e.g. 12, not 0.12)
- Compare frequencies — a higher compounding frequency yields more interest towards the end, which the chart makes easy to see
Verdict
The Compound Interest Calculator takes your principal, rate, time, and optional contributions, and returns a clear balance with a growth chart across any compounding frequency.