EMI Calculator for Loans, Monthly breakdown of EMI in Principal and Interest components - www.koffeewithkode.com

loan-emi-calculator.js

/* 
By: Manish (www.koffeewithkode.com)
*/

function calculateEMI(principal, rate_percent, time_in_months, precision) {

    var EMI;
    var rate_per_month = (rate_percent / 12) / 100; //divide the rate by 100 and 12
    var numr = Math.pow((1 + rate_per_month), time_in_months);
    var denr = (Math.pow((1 + rate_per_month), time_in_months) - 1);

    EMI = principal * rate_per_month * (numr / denr);

    //round the EMI to two decimal points
    EMI = EMI.toFixed(precision);

    var total_payment = EMI * time_in_months;
    var total_interest = total_payment - principal;

    var data_obj = [];

    var principal_by_month = principal;

    // loop through each month and calculate
    // each months principal component and the interest component

    for (var i = 1; i <= time_in_months; i++) {
        var each_months_principal, each_months_interest;
        each_months_interest = principal_by_month * rate_per_month;
        var principal_component = EMI - each_months_interest;
        var interest_component = each_months_interest;

        var balance_principal = principal_by_month - principal_component;
        if (balance_principal < 0) {
            balance_principal = 0;
        }
        var single_month_data = [principal_component, interest_component, balance_principal];
        data_obj.push(single_month_data);
        principal_by_month = principal_by_month - principal_component;
    }
  
    var result = new Array();
    result['principal'] = principal;
    result['time_in_months'] = time_in_months;
    result['rate_percent'] = rate_percent;
    result['emi'] = EMI;
    result['total_interest'] = total_interest.toFixed(precision);
    result['total_payment'] = total_payment.toFixed(precision);
    result['data_obj'] = data_obj;

    return result;
}