APR Loan Calculator
body {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f8f9fa;
color: #333;
line-height: 1.6;
margin: 0;
padding: 20px;
}
.loan-calc-container {
max-width: 700px;
margin: 30px auto;
background-color: #ffffff;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
padding: 30px;
overflow: hidden;
}
h1, h2 {
color: #004a99;
text-align: center;
margin-bottom: 20px;
}
.input-group {
margin-bottom: 20px;
padding: 15px;
border: 1px solid #e0e0e0;
border-radius: 5px;
background-color: #fdfdfd;
}
.input-group label {
display: block;
margin-bottom: 8px;
font-weight: 500;
color: #004a99;
}
.input-group input[type="number"],
.input-group input[type="text"] {
width: calc(100% – 20px);
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 1rem;
margin-top: 5px;
}
.input-group input[type="number"]:focus,
.input-group input[type="text"]:focus {
border-color: #004a99;
outline: none;
box-shadow: 0 0 0 3px rgba(0, 74, 153, 0.2);
}
.button-group {
text-align: center;
margin-top: 25px;
}
button {
background-color: #004a99;
color: white;
border: none;
padding: 12px 25px;
border-radius: 5px;
font-size: 1.1rem;
cursor: pointer;
transition: background-color 0.3s ease;
}
button:hover {
background-color: #003366;
}
#result {
margin-top: 30px;
padding: 20px;
background-color: #e6f2ff;
border-left: 5px solid #28a745;
border-radius: 5px;
text-align: center;
}
#result h3 {
margin-top: 0;
color: #004a99;
font-size: 1.4rem;
}
#result-value {
font-size: 2rem;
font-weight: bold;
color: #28a745;
}
.explanation {
margin-top: 40px;
padding: 25px;
background-color: #eef5ff;
border-radius: 8px;
border: 1px solid #d1e4ff;
}
.explanation h2 {
margin-top: 0;
text-align: left;
color: #004a99;
}
.explanation p, .explanation ul {
margin-bottom: 15px;
}
.explanation ul {
list-style-type: disc;
margin-left: 20px;
}
.explanation strong {
color: #004a99;
}
@media (max-width: 768px) {
.loan-calc-container {
margin: 20px auto;
padding: 20px;
}
button {
width: 100%;
padding: 15px;
}
}
function calculateAPR() {
var loanAmount = parseFloat(document.getElementById("loanAmount").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var loanTermMonths = parseFloat(document.getElementById("loanTermMonths").value);
var originationFeePercent = parseFloat(document.getElementById("originationFeePercent").value);
var otherFees = parseFloat(document.getElementById("otherFees").value);
var errorMessage = "";
if (isNaN(loanAmount) || loanAmount <= 0) {
errorMessage += "Please enter a valid loan amount greater than zero.\n";
}
if (isNaN(interestRate) || interestRate < 0) {
errorMessage += "Please enter a valid interest rate (0 or greater).\n";
}
if (isNaN(loanTermMonths) || loanTermMonths <= 0) {
errorMessage += "Please enter a valid loan term in months greater than zero.\n";
}
if (isNaN(originationFeePercent) || originationFeePercent < 0) {
errorMessage += "Please enter a valid origination fee percentage (0 or greater).\n";
}
if (isNaN(otherFees) || otherFees 0) {
monthlyPayment = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, loanTermMonths)) / (Math.pow(1 + monthlyInterestRate, loanTermMonths) – 1);
} else {
monthlyPayment = loanAmount / loanTermMonths;
}
var totalInterestPaid = (monthlyPayment * loanTermMonths) – loanAmount;
var totalRepaid = monthlyPayment * loanTermMonths;
var originationFeeAmount = loanAmount * (originationFeePercent / 100);
var totalFees = originationFeeAmount + otherFees;
var totalCostOfLoan = loanAmount + totalInterestPaid + totalFees;
// Calculate APR
// This is an iterative approximation as there's no direct formula for APR
var apr = 0;
var low = 0.0001; // Lower bound for APR search
var high = 1.0; // Upper bound for APR search (100%)
var iterations = 0;
var epsilon = 0.00001; // Tolerance for accuracy
// Effective loan amount after initial fees
var effectiveLoanAmount = loanAmount – originationFeeAmount – otherFees;
if (effectiveLoanAmount <= 0) {
document.getElementById("result-value").innerHTML = "N/A";
document.getElementById("result-description").innerHTML = "Fees exceed loan amount. Cannot calculate APR.";
return;
}
while (iterations 0) {
calculatedPayment = effectiveLoanAmount * (monthlyRate * Math.pow(1 + monthlyRate, loanTermMonths)) / (Math.pow(1 + monthlyRate, loanTermMonths) – 1);
} else {
calculatedPayment = effectiveLoanAmount / loanTermMonths;
}
var difference = calculatedPayment – monthlyPayment;
if (Math.abs(difference) < epsilon) {
apr = mid;
break;
} else if (difference = 100) {
// A common approximation formula for APR, especially for simpler loans
// This is less precise than the iterative method but provides a fallback
var factor = Math.pow(1 + (interestRate / 100), loanTermMonths);
var principalUsedForAPR = loanAmount – (originationFeeAmount + otherFees); // Cost basis for APR
if (principalUsedForAPR <= 0) {
apr = interestRate / 100; // Fallback to nominal rate if fees are too high
} else {
var totalPayments = (monthlyPayment * loanTermMonths);
var costOfCredit = totalPayments – principalUsedForAPR;
apr = ( (costOfCredit / principalUsedForAPR) / loanTermMonths ) * 12 * 100;
// A simple approximation, can be inaccurate for complex fee structures
// For better accuracy, stick to the iterative method if possible.
// If iterative method failed, this provides a rough estimate.
}
// Ensure APR is within reasonable bounds if approximation is way off
if (apr 5) apr = 5; // Cap at 500% nominal rate for approximation safeguard
}
document.getElementById("result-value").innerHTML = apr.toFixed(3) + "%";
document.getElementById("result-description").innerHTML = "This is the estimated Annual Percentage Rate (APR), which includes the interest rate plus certain fees, expressed as a yearly rate. It offers a more comprehensive cost of borrowing than the interest rate alone.";
}
APR Loan Calculator
Enter loan details to calculate your APR.
—
Understanding the APR Loan Calculator
The Annual Percentage Rate (APR) is a crucial figure for borrowers because it represents the total cost of borrowing money over a year, expressed as a percentage. Unlike the simple interest rate, APR includes not only the interest charged on the loan but also most fees and other charges associated with obtaining the loan. This makes it a more comprehensive measure of the true cost of a loan.
How the APR is Calculated
Calculating the exact APR can be complex, especially when fees are involved. The APR calculation aims to find a single annual interest rate that, when used to calculate monthly payments, results in the same total repayment amount as the actual loan terms, considering all fees. The formula for monthly loan payments is:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
M = Monthly Payment
P = Principal Loan Amount
i = Monthly Interest Rate (Annual Rate / 12)
n = Total Number of Payments (Loan Term in Months)
However, for APR, the 'P' effectively becomes the loan amount minus the upfront fees (like origination fees and other charges). The APR calculation requires finding the interest rate 'i' that makes the calculated monthly payment 'M' (based on the loan amount minus fees) equal to the actual monthly payment derived from the stated interest rate and original principal. Since there's no direct algebraic solution for 'i' in this scenario, it's typically calculated using iterative methods (like a financial calculator or software) or by using an approximation formula.
Our calculator uses an iterative process to find the most accurate APR. It adjusts the interest rate iteratively until the monthly payment calculated with that rate matches the monthly payment of the loan with its associated fees.
Key Inputs Explained
Loan Amount ($): The total amount of money you are borrowing before any fees are deducted.
Annual Interest Rate (%): The stated interest rate of the loan per year, without considering fees.
Loan Term (Months): The total duration of the loan, expressed in months.
Origination Fee (%): A fee charged by the lender for processing the loan, usually a percentage of the loan amount.
Other Fees ($): Any additional fees associated with the loan that are not included in the origination fee (e.g., application fees, processing fees).
Why APR Matters
When comparing different loan offers, the APR provides a standardized way to see which loan is truly cheaper. A loan with a lower interest rate might not be the best deal if it has significantly higher fees. Always compare the APRs of different loans to understand the total cost of borrowing.
Note: Not all lender fees are factored into the APR calculation by law (e.g., late payment fees, NSF fees). Always read the loan agreement carefully.