mortgage-js

Simple mortgage calculator written in Javascript. Determine total monthly payment. Calculate entire payment schedule with principal and interest. See how additional principal payments could affect the pay down schedule. Also accounts for property tax, homeowner insurance and private mortgage insurance.

Install with NPM

npm install --save mortgage-js

Usage

mortgageJs = require("mortgage-js")

let mortgageCalculator = mortgageJs.createMortgageCalculator();
mortgageCalculator.totalPrice = 800000;
mortgageCalculator.downPayment = 160000;
mortgageCalculator.interestRate = 0.045;
mortgageCalculator.months = 360;
mortgageCalculator.taxRate = 0.012;
mortgageCalculator.insuranceRate = 0.0013;
mortgageCalculator.mortgageInsuranceRate = 0.010;
mortgageCalculator.mortgageInsuranceEnabled = true;
mortgageCalculator.mortgageInsuranceThreshold = 0.2;
mortgageCalculator.additionalPrincipalPayment = 100;
let payment = mortgageCalculator.calculatePayment();

Alternate Usage

mortgageJs = require("mortgage-js")

let payment = mortgageJs.calculatePayment(800000,
        160000,
        0.045,
        360,
        0.012,
        0.0013,
        0.010,
        true,
        0.2,
        100);

Payment Model

{
    loanAmount: number, // Total loan amount. Price - Down Payment
    principalAndInterest: number, // Portion of payment that goes towards principal & interest.
    tax: number, // Property tax
    insurance: number, // Homeowner insurance
    total: number, // Total monthly payment
    termMonths: number, // Number of monthly payments
    mortgageInsurance: number, // Private mortgage insurance. Only relevant with lower down payments.
    paymentSchedule: [
        {
            count: number, // The payment number starting with 1
            interestPayment: number, // The portion of payment that is an interest charge
            totalInterest: number, // The total interest that has been paid thus far
            principalPayment: number, // The portion of payment that goes towards the principal balance
            totalPayment: number, // The total payment amount
            totalPayments: number, // The total of payments that have been made thus far
            balance: number // The remaining balance after payment has been applied
        }
    ]
}

Running Tests

npm test

Release

1. Commit changes
2. Increment version with: npm version major|minor|patch
3. Push changes to origin master
4. npm publish