Mortgage Payoff Goal Calculator Code

First you will need to add the following between the <HEAD> </HEAD> tags of your page.

if(Vnum > 99000000) {
alert("Sorry, this will not generate numbers larger that 99 million.");
focus();
} else {
   
var V10million = parseInt(Vnum / 10000000);
var V1million = (Vnum % 10000000)  / 1000000;
if(V1million / 1000000 == 1) { V1million = 1; } else
if(V1million < 1) { V1million = "0"; } else { V1million = parseInt(V1million,10); }

var V10thousand = (Vnum % 100000)  / 10000;
if(V10thousand / 10000 == 1) { V10thousand = 1; } else
if(V10thousand < 1) { V10thousand = "0"; } else { V10thousand = parseInt(V10thousand,10); }

var V1thousand = (Vnum % 10000)  / 1000;
if(V1thousand / 1000 == 1) { V1thousand = 1; } else
if(V1thousand < 1) { V1thousand = "0"; } else { V1thousand = parseInt(V1thousand,10); }

var Vhundreds = (Vnum % 1000)  / 100;
if(Vhundreds / 100 == 1) { Vhundreds = 1; } else
if(Vhundreds < 1) { Vhundreds = "0"; } else { Vhundreds = parseInt(Vhundreds,10); }

var Vtens = (Vnum % 100)  / 10;
if(Vtens / 10 == 1) { Vtens = 1; } else
if(Vtens < 1) { Vtens = "0"; } else { Vtens = parseInt(Vtens,10); }

var Vones = (Vnum % 10)  / 1;
if(Vones / 1 == 1) { Vones = 1; } else
if(Vones < 1) { Vones = "0"; } else { Vones = parseInt(Vones,10); }

//START UPGRADE
var Vcents = 0;

if(Vnum % 1 * 100 < 1) { Vcents = 0; } else { Vcents = parseInt(((eval(Vnum % 1) * 100)),10); }
//END UPGRADE

if(Vcents < 1) { Vcents = "00"; }
else
if(Vcents % 10 == 0) { Vcents = Vcents + "0"; }
else
if(Vcents % 10 == Vcents) { Vcents = "0" + Vcents; } else { Vcents = Vcents; }

if(Vcents == "900") { Vcents = "90"; } else
if(Vcents == "800") { Vcents = "80"; } else 
if(Vcents == "700") { Vcents = "70"; } else 
if(Vcents == "600") { Vcents = "60"; } else 
if(Vcents == "500") { Vcents = "50"; } else 
if(Vcents == "400") { Vcents = "40"; } else 
if(Vcents == "300") { Vcents = "30"; } else
if(Vcents == "200") { Vcents = "20"; } else
if(Vcents == "100") { Vcents = "10"; } else { Vcents = Vcents; }
   
var Vformat = "";

if(Vnum >= 10000000) { Vformat = (V10million + "" + V1million + "," + V100thousand + "" + V10thousand + "" + V1thousand + "," + Vhundreds + "" + Vtens + "" + Vones + "." + Vcents); }
else
if(Vnum >= 1000000) { Vformat = (V1million + "," + V100thousand + "" + V10thousand + "" + V1thousand + "," + Vhundreds + "" + Vtens + "" + Vones + "." + Vcents); }
else
if(Vnum >= 100000) { Vformat = (V100thousand + "" + V10thousand + "" + V1thousand + "," + Vhundreds + "" + Vtens + "" + Vones + "." + Vcents); }
else
if(Vnum >= 10000) { Vformat = (V10thousand + "" + V1thousand + "," + Vhundreds + "" + Vtens + "" + Vones + "." + Vcents); }
else
if(Vnum >= 1000) { Vformat = (V1thousand + "," + Vhundreds + "" + Vtens + "" + Vones + "." + Vcents); }
else
if(Vnum >= 100) { Vformat = (Vhundreds + "" + Vtens + "" + Vones + "." + Vcents); }
else
if(Vnum >= 10) { Vformat = (Vtens + "" + Vones + "." + Vcents); }
else
if(Vnum >= 1) { Vformat = (Vones + "." + Vcents); } else { Vformat = ("0." + Vcents); }

return Vformat;
  }
}

function computeForm(form) {

if(form.principal.value == "" || form.principal.value == 0) {
alert("Please enter the principal balance of your current mortgage.");
form.principal.focus();
} else
if(form.interest.value == "" || form.interest.value == 0) {
alert("Please enter the interest rate of your current mortgage.");
form.interest.focus();
} else
if(form.origPmt.value == "" || form.origPmt.value == 0) {
alert("Please your current monthly mortgage payment.");
form.origPmt.focus();
} else
if(form.noYears.value == "" || form.noYears.value == 0) {
alert("Please enter the number of years you would like to pay off your mortgage in.");
form.noYears.focus();
} else {

var i = form.interest.value;
if (i > 1.0) { i = i / 100.0; }
i /= 12;
VnoYears = form.noYears.value;
VorigPmt = form.origPmt.value;
var noMonths = VnoYears * 12;
var pow = 1;
    for (var j = 0; j < noMonths; j++)
        pow = pow * (1 + i);
var newPmt = (form.principal.value * pow * i) / (pow - 1);
var VpmtAdd = eval(newPmt) - eval(VorigPmt);
form.pmtAdd.value = "$" + formatNum(VpmtAdd);
var prin = form.principal.value;
var count = 0;
var prinPort = 0;
var intPort = 0;
var accumInt = 0;
var pmt = form.origPmt.value;

while(eval(prin) > eval(pmt)) {
intPort = prin * i;
accumInt = eval(accumInt) + eval(intPort)
prinPort = eval(pmt) - eval(intPort);
prin = eval(prin) - eval(prinPort);
count = eval(count) + eval(1);
}

var VorigInt = accumInt;
var VnewInt = (eval(newPmt * noMonths)) - eval(form.principal.value);
var VintSave = eval(VorigInt) - eval(VnewInt);

form.intSave.value = "$" + formatNum(VintSave);

var Vresults = ("If you would like to pay off your mortgage in " + VnoYears + " years instead of the current " + formatNum(count / 12) + " years, you will need to start making a second monthly mortgage payment in the amount of " + form.pmtAdd.value + ". This will cut your current mortgage interest cost from $" + formatNum(accumInt) + " down to $" + formatNum(VnewInt) + ", a savings of " + form.intSave.value + " in interest charges.");

form.results.value = Vresults;
 }
}

function clearForm(form)
{
form.principal.value = "";
form.interest.value = "";
form.origPmt.value = "";
form.noYears.value = "";
form.pmtAdd.value = "";
form.intSave.value = "";
form.results.value = "";
}

</script>

Then place the following code on the page where you wish the calculator to appear.

<form method=post>
<center>
<table style="border: 1px solid black;" bgcolor="#ffffff" cellspacing=0 cellpadding=0>
<tr>
	<td align=right width=50%>
			<font size=2 face="arial,helvetica" color="#000000"> <b>Enter the principal balance owed:</b> </font>
	</td>
	<td align=left width=50%>
		<input type=text name="principal" size=15>
	</td>
</tr>
<tr>
	<td align=right>
		<font size=2 face="arial,helvetica" color="#000000"> <b>Enter the annual interest rate:</b> </font>
	</td>
	<td align=left>
		<input type=text name="interest" size=15>
	</td>
</tr>
<tr>
	<td align=right>
		<font size=2 face="arial,helvetica" color="#000000"> <b>Enter the current monthly payment amount:</b> </font>
	</td>
	<td align=left>
		<input type=text name="origPmt" size=15>
	</td>
</tr>
<tr>
	<td align=right>
		<font size=2 face="arial,helvetica" color="#000000"> <b># of years you wish to pay off mortgage in:</b> </font>
	</td>
	<td align=left>
		<input type=text name="noYears" size=15>
	</td>
</tr>
<tr>
<TD colsPAN="2">
<a href="http://www.300mortgagelenders.com/"><img src="http://www.300mortgagelenders.com/images/spacer.gif" border=0 height=10></a>
</td>
</tr>
<tr>
<TD colsPAN="2">
<center><input type="button" value="Compute" onClick="computeForm(this.form)"> <input type="button" value="Clear Form"  onClick="clearForm(this.form)"></center>
</td>
</tr>
<tr>
<TD colsPAN="2">
<a href="http://www.300mortgagelenders.com/"><img src="http://www.300mortgagelenders.com/images/spacer.gif" border=0 height=10></a>
</td>
</tr>

<tr>
	<td align=right>
		<font size=2 face="arial,helvetica" color="#000000"> <b>Additional monthly payment required:</b> </font>
	</td>
	<td align=left>
		<input type=text name="pmtAdd" size=15>
	</td>
</tr>
<tr>
	<td align=right>
		<font size=2 face="arial,helvetica" color="#000000"> <b>Interest savings:</b> </font>
	</td>
	<td align=left>
		<input type=text name="intSave" size=15>
	</td>
</tr>

<tr>
<td colspan="2">
<center><textarea cols=55 ROWS=7 name="results" wrap=virtual></textarea></center><br>
<font size=1 face="verdana,arial,helvetica" color="#000000">
This calculator will show you the additional monthly payment you will need to make on your current mortgage in order to pay if off within a specified number of years. It will also show you how much interest you will save if you make the calculated additional payment each month, from now until your mortgage is paid off. Special thanks to online subscriber Lyle Crafton for presenting the idea for this calculator.<br>
<br>
NOTE:  Be sure to enter "0" (zero) in any entry boxes that don't apply to you.  Also be sure that only numbers and decimal points are entered into the fields (dollar signs and other non-numeric characters will cause a JavaScript error).<br></font>
</td></tr></table></center></form>

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