# Loan Calculator

> Calculate payment, interest, total cost, and the effect of an optional extra payment.

Page: https://askcalculators.com/calculator/loan-calculator/
Definition: https://askcalculators.com/calculator/loan-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/loan-calculator/schema.json
Version: 1.0.0
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/loan-calculator/?amount=25000&annualRate=7.5&years=5

## Inputs
- amount: Loan amount; type=money; required; default=25000; min=1
- annualRate: Interest rate; type=percent; required; default=7.5; min=0; max=40
- years: Loan term; type=select; required; default=5; values=1|2|3|5|7|10
- extraPayment: Extra monthly payment; type=money; optional; min=0

## Outputs
- monthlyPayment: Scheduled monthly payment; format=currency; primary
- paymentWithExtra: Payment with extra; format=currency
- totalInterest: Total interest; format=currency
- totalPayment: Total paid; format=currency
- payoffTime: Payoff time; format=text
- interestSaved: Interest saved; format=currency

## Formula
M = P × [r(1 + r)ⁿ] ÷ [(1 + r)ⁿ − 1]

- P: loan principal
- r: monthly rate
- n: monthly payment count

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