# Investment Calculator

> Project the growth of your investments over time with compound interest.

Page: https://askcalculators.com/calculator/investment-calculator/
Definition: https://askcalculators.com/calculator/investment-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/investment-calculator/schema.json
Version: 7.1.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/investment-calculator/?startAmount=10000&monthlyContrib=500&rate=7&years=10

## Inputs
- startAmount: Starting Amount; type=number; optional; default=10000
- monthlyContrib: Monthly Contribution; type=number; optional; default=500
- rate: Return Rate; type=number; optional; default=7
- years: Time Period (Years); type=number; optional; default=10

## Outputs
- result: Result; format=text; primary

## Formula
Months = round(years × 12). Each month: balance = balance × (1 + annual nominal return / 1200) + monthly contribution.

Contributions occur at month end. Partial years round to the nearest month; the annual nominal percentage is divided by 12. Taxes, fees and inflation are excluded; returns are scenarios, not predictions.

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.

Notice: Contributions are added at month end. Partial years round to the nearest month. Investment returns are hypothetical and may be negative; taxes, fees and inflation are not included.