Simple loan simulation on WordPress

Insert following code on function.php on your theme.

function kpr() {
    ob_start(); ?>
    <div class="kpr-frame">
            <form>
                <label>Harga</label>
                <input type="number" class="form-control mb-2" id="harga" placeholder="Contoh: 250000000" required>
                <label>DP</label>
                <input type="number" class="form-control mb-2" id="dp" placeholder="Contoh: 25000000" required>
                <label>Jangka Waktu (Tahun) </label>
                <input type="number" class="form-control mb-2" id="tenor" placeholder="Contoh: 10" required>
                <label>Suku Bunga /tahun (%)</label>
                <input type="number" class="form-control" id="bunga" placeholder="Contoh: 2" required>
                <label></label>
                <button id="hitungsimulasi" class="btn btn-outline-primary btn-lg btn-block">Hitung</button>
            </form>
    <script>
jQuery(function($) {
    function convertToRupiah(angka)
    {
    	var rupiah = '';		
    	var angkarev = angka.toString().split('').reverse().join('');
    	for(var i = 0; i < angkarev.length; i++) if(i%3 == 0) rupiah += angkarev.substr(i,3)+'.';
    	return 'Rp. '+rupiah.split('',rupiah.length-1).reverse().join('');
    }
    $("#hitungsimulasi").click(function(event) {
        var harga           = $('#harga').val();
        var tenor           = $('#tenor').val();
        var tenortahun      = tenor*12;
        var bunga           = $('#bunga').val();
        var dp              = $('#dp').val();
        var kurang          = +harga - +dp;
        var cicilpokok       = +kurang / tenortahun;
        var rpbunga          = +kurang*((bunga/100)/12);
        var bungadibayar    = +kurang*((bunga*tenor)/100);
        var angsuran        = (kurang+bungadibayar)/tenortahun;
        var totaldp         = + dp + +angsuran;
        var tpinjaman       = '<<br><br>div class="alert alert-dark" role="alert"> Total Pinjaman: '+ convertToRupiah(Math.round(kurang)) +'</div>';
        var cicilanpokok       = '<div class="alert alert-dark" role="alert"> Cicilan Pokok: '+ convertToRupiah(Math.round(cicilpokok)) +'</div>';
        var bungarp       = '<div class="alert alert-dark" role="alert">Bunga: '+convertToRupiah(Math.round(rpbunga))+'</div>';
        var tuangmuka       = '<div class="alert alert-dark" role="alert">Total DP + Cicilan Pertama: '+convertToRupiah(Math.round(totaldp))+'</div>';
        var tangsuran       = '<div class="alert alert-info" role="alert">Angsuran per bulan<br><b>'+convertToRupiah(Math.round(angsuran))+'</b> <small> *selama '+tenor+' tahun ('+tenortahun+' Bulan)</small></div>';
        if(!harga){
            $('.hasilhitung').html('<div class="alert alert-warning" role="alert">Harga belum Diisi.</div>');
        } else if (!dp){
            $('.hasilhitung').html('<div class="alert alert-warning" role="alert">Tentukan DP. Contoh 25.000.000</div>');
        } else if (!bunga) {
            $('.hasilhitung').html('<div class="alert alert-warning" role="alert">Tentukan Bunga. Contoh 10</div>');
        } else {
            $('.hasilhitung').html('<div class="">'+  tpinjaman + cicilanpokok + bungarp + tuangmuka + tangsuran + '</div>');
        }
        event.preventDefault();
    });
});
    </script>
    
 <div class="hasilhitung mt-3"></div>     
    
</div>
    <?php return ob_get_clean();
}
add_shortcode('kpr', 'kpr');

This is flat loan simulation with following formula:

a = loan principal
b = interest per tahun
c = time in year
d = downpayment

so,

installment per month = (a-d) / c
interest per month = (a-d) x b / 12
Total  installament per month = (a-d) x b / 12 x c

for using this simulation using this shortcode:

[kpr]