function calculate() {
	//the calc button
	var button = document.getElementById('CalcButton');

	//inputs
	var LoanAmount = document.getElementById('LoanAmount');
	var InterestRate = document.getElementById('InterestRate');

	LoanAmount.value = toNumber(LoanAmount.value);
	InterestRate.value = toNumber(InterestRate.value);

	//outputs
	var PrincipleAndInterest = document.getElementById('PrincipleAndInterest');
	var InterestOnlyPayment = document.getElementById('InterestOnlyPayment');
	var Savings = document.getElementById('Savings');

	//compute Regular Principal and Interest Payment
	var PandICalc = compute_payment(LoanAmount.value, InterestRate.value, 360, 12);
	PrincipleAndInterest.innerHTML = formatAsMoney(PandICalc);

	//compute the interest only payment
	var IOPayment = (LoanAmount.value * InterestRate.value) / 12 / 100;
	InterestOnlyPayment.innerHTML = formatAsMoney(IOPayment);

	//compute savings
	var SavingsCalc = PandICalc - IOPayment;
	Savings.innerHTML = formatAsMoney(SavingsCalc);

	button.disabled = false;
}