# Interest Calculator

> Project compound growth with a nominal annual rate, selected compounding frequency, and end-of-month contributions.

Page: https://askcalculators.com/calculator/interest-calculator/
Definition: https://askcalculators.com/calculator/interest-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/interest-calculator/schema.json
Version: 7.0.0
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/interest-calculator/?principal=10000&rate=5&time=10&contribution=0&compoundFreq=12

## Inputs
- principal: Principal Amount; type=number; optional; default=10000
- rate: Annual Interest Rate; type=number; optional; default=5
- time: Time Period (Years); type=number; optional; default=10
- contribution: Monthly Contribution; type=number; optional; default=0
- compoundFreq: Compounding Frequency; type=text; optional; default=12

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

## Formula
Effective monthly rate = (1 + nominal annual rate ÷ compounds per year)^(compounds per year ÷ 12) − 1; each month balance grows by that rate, then the entered contribution is added.

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