How to use this calculator
Explore growth with monthly contributions. Enter starting balance ($), monthly contribution ($), assumed annual return (%), years (whole-month increments). The result updates when you change an input. To compare two sets of inputs, save scenario A, then enter the second set; the result panel shows the difference.
Formula and limits
Monthly compounding at annual rate ÷ 12, with contributions at the end of each month. Enter a duration that represents a whole number of months (for example, 1 or 1.25 years). The result shows the month count used. Constant return, no taxes, fees, or inflation. Assumed returns are not guaranteed.
Worked example
The following example uses the calculator’s starting values. It is an illustration of the method, not a recommended target.
| Input | Example value |
|---|---|
| Starting balance ($) | 10000 |
| Monthly contribution ($) | 200 |
| Assumed annual return (%) | 5 |
| Years (whole-month increments) | 10 |
Projected balance: $47,526.55
Duration: 120 months · Contributed: $34,000.00
Interpreting your result
Treat the output as a planning estimate. Enter your own current rates and costs; defaults are examples, not current offers. Taxes, fees, variable rates, and lender conventions may change the actual outcome.
Comparing alternatives
Save the first result as scenario A, then change one input. The comparison shows the numeric difference; it does not label either result as better. Choose inputs that describe realistic alternatives. Values shown on screen are rounded, so calculations from rounded intermediate results may differ slightly.
Background reading
Investor.gov financial tools. This is a subject reference, not an endorsement or independent review of Calcaven.