10 Interest Rate Calculator

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Compound Interest Calculator body { font-family: Arial, sans-serif; margin: 20px; } .calculator-container { border: 1px solid #ccc; padding: 20px; border-radius: 8px; max-width: 500px; margin: auto; background-color: #f9f9f9; } label { display: block; margin-bottom: 5px; font-weight: bold; } input[type="number"] { width: calc(100% – 12px); padding: 8px; margin-bottom: 15px; border: 1px solid #ddd; border-radius: 4px; } button { background-color: #4CAF50; color: white; padding: 10px 15px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; } button:hover { background-color: #45a049; } #result { margin-top: 20px; padding: 10px; background-color: #e7f3fe; border-left: 6px solid #2196F3; border-radius: 4px; } h1 { text-align: center; color: #333; } p { line-height: 1.6; color: #555; } .explanation { margin-top: 30px; padding: 20px; border-top: 1px solid #eee; }

Compound Interest Calculator

Understand how your money grows over time with compound interest. Input your initial investment, the annual interest rate, the number of times interest is compounded per year, and the duration of your investment.

What is Compound Interest?

Compound interest, often called "interest on interest," is the process where the interest earned on an investment is added to the principal amount. This new, larger principal then earns interest in the subsequent period. Over time, this effect can significantly accelerate the growth of your investments compared to simple interest, where interest is only calculated on the initial principal.

How Compound Interest Works:

Imagine you invest $1,000 at an annual interest rate of 5%, compounded annually. After the first year, you earn $50 in interest (5% of $1,000). Your total balance is now $1,050. In the second year, you earn interest on this new balance. So, you earn $52.50 in interest (5% of $1,050), bringing your total to $1,102.50. This process of earning interest on previously earned interest is the power of compounding.

The Compound Interest Formula:

The future value of an investment with compound interest can be calculated using the following formula:

A = P (1 + r/n)^(nt)

Where:

  • 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

Why Use This Calculator?

This calculator helps you visualize the potential growth of your savings or investments. By experimenting with different initial amounts, interest rates, compounding frequencies, and time periods, you can better understand the impact of these variables and make informed financial decisions. It's a powerful tool for estimating future wealth accumulation.

function calculateCompoundInterest() { var principal = parseFloat(document.getElementById("principal").value); var rate = parseFloat(document.getElementById("rate").value); var time = parseFloat(document.getElementById("time").value); var n_compounding = parseFloat(document.getElementById("n_compounding").value); var resultDiv = document.getElementById("result"); // Validate inputs if (isNaN(principal) || principal < 0 || isNaN(rate) || rate < 0 || isNaN(time) || time < 0 || isNaN(n_compounding) || n_compounding <= 0) { resultDiv.innerHTML = "Error: Please enter valid positive numbers for all fields. The number of compounding periods per year must be greater than zero."; return; } // Convert rate from percentage to decimal var r_decimal = rate / 100; // Calculate compound interest var amount = principal * Math.pow((1 + r_decimal / n_compounding), (n_compounding * time)); var interestEarned = amount – principal; resultDiv.innerHTML = "

Calculation Results:

" + "Initial Investment: $" + principal.toFixed(2) + "" + "Annual Interest Rate: " + rate.toFixed(2) + "%" + "Investment Duration: " + time.toFixed(0) + " years" + "Compounded: " + n_compounding.toFixed(0) + " times per year" + "
" + "Total Amount After " + time.toFixed(0) + " Years: $" + amount.toFixed(2) + "" + "Total Interest Earned: $" + interestEarned.toFixed(2) + ""; }

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