Simple Interest Calculator
This calculator helps you determine the simple interest earned on an investment or the simple interest paid on a loan. Simple interest is calculated only on the principal amount, or on that portion of the loan amount that is still outstanding.
function calculateSimpleInterest() {
var principal = parseFloat(document.getElementById("principal").value);
var rate = parseFloat(document.getElementById("rate").value);
var time = parseFloat(document.getElementById("time").value);
var resultDiv = document.getElementById("result");
if (isNaN(principal) || isNaN(rate) || isNaN(time) || principal < 0 || rate < 0 || time < 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// Formula for Simple Interest: SI = (P * R * T) / 100
var interest = (principal * rate * time) / 100;
var totalAmount = principal + interest;
resultDiv.innerHTML = "
Results:
" +
"
Simple Interest Earned/Paid: $" + interest.toFixed(2) + "" +
"
Total Amount (Principal + Interest): $" + totalAmount.toFixed(2) + "";
}
.calculator-container {
font-family: sans-serif;
border: 1px solid #ccc;
padding: 20px;
border-radius: 5px;
max-width: 500px;
margin: 20px auto;
background-color: #f9f9f9;
}
.calculator-container h2 {
text-align: center;
margin-bottom: 20px;
color: #333;
}
.calculator-form {
display: flex;
flex-direction: column;
gap: 15px;
}
.form-group {
display: flex;
flex-direction: column;
}
.form-group label {
margin-bottom: 5px;
font-weight: bold;
color: #555;
}
.form-group input {
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 1rem;
}
.calculator-container button {
padding: 12px 20px;
background-color: #007bff;
color: white;
border: none;
border-radius: 4px;
font-size: 1.1rem;
cursor: pointer;
transition: background-color 0.3s ease;
}
.calculator-container button:hover {
background-color: #0056b3;
}
.calculator-result {
margin-top: 20px;
padding: 15px;
background-color: #e9ecef;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 1rem;
color: #333;
}
.calculator-result h3 {
margin-top: 0;
color: #0056b3;
}