compound interest with regular intervals

compound_interest_with_regular_intervals.js

     let princ = 10000; // start deposit
    let add = 500; // monthly deposit (need plus it every year)
    let rate = 0.06; // interest rate divided to create decimal
    let months = (41 * 12); //41 years of monthly contributions
    for (let i = 1; i <= months; i++) {

        princ += princ * (rate / 12);
        princ += add;
        console.log(princ);
    }
    console.log(princ.toFixed(2));