Compound Interest Calculator
Understanding compound interest is crucial for growing your investments over time. Compound interest is the interest calculated on the initial principal, which also includes all of the accumulated interest from previous periods. It's often referred to as "interest on interest." This means your money grows at an accelerating rate, as your earnings start earning their own earnings.
The formula for compound interest is: A = P (1 + r/n)^(nt)
- A = the future value of the investment/loan, including interest
- P = the principal investment amount (the initial deposit or loan amount)
- r = the annual interest rate (as a decimal)
- n = the number of times that interest is compounded per year
- t = the number of years the money is invested or borrowed for
Use this calculator to see how your investment can grow with compounding.
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font-size: 18px;
color: #333;
min-height: 50px; /* Ensure it's visible even when empty */
display: flex;
align-items: center;
justify-content: center;
}
function calculateCompoundInterest() {
var principal = parseFloat(document.getElementById("principal").value);
var annualRate = parseFloat(document.getElementById("annualRate").value);
var compoundingFrequency = parseInt(document.getElementById("compoundingFrequency").value);
var years = parseFloat(document.getElementById("years").value);
var resultElement = document.getElementById("result");
if (isNaN(principal) || isNaN(annualRate) || isNaN(compoundingFrequency) || isNaN(years) ||
principal <= 0 || annualRate < 0 || compoundingFrequency <= 0 || years <= 0) {
resultElement.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// Convert annual rate percentage to decimal
var rateDecimal = annualRate / 100;
// Calculate future value using the compound interest formula
// A = P (1 + r/n)^(nt)
var futureValue = principal * Math.pow((1 + rateDecimal / compoundingFrequency), (compoundingFrequency * years));
// Display the result, formatted to two decimal places
resultElement.innerHTML = "Future Value: $" + futureValue.toFixed(2);
}