# Calculate Simple Interest in Javascript

In this tutorial, I will show you the program for how to calculate simple interest in javascript.

## What is simple Interest:

Simple interest is the interest on a loan that is calculated and charged only on the principal balance of the loan. It is calculated by multiplying the principle amount, rate of interest, and a number of years and dividing it by 100.

Simple Interest Formula = (P x T x R)/100
Where P: principle amount, T: time, and R: Interest rate
For example, if you borrow \$10,000 for one year at an annual interest rate of 10%, you will pay the interest of \$1,000 and \$11,000 in total.

## Program to calculate simple interest in javascript

Let’s create a simple program to calculate the simple interest in javascript. The code is straightforward.

``````// Function to Calculate Simple Interest in Javascript.
function calculateInterest(p, r, t) {
return (p*r*t) / 100
}

console.log(calculateInterest(10000, 10, 1))``````

### Result:

``1000``

## Program to calculate the total amount to be paid

Let’s also create a function that will return the total payable amount (principle + interest).

Total Amount Formula:
A = P x (1 + RT)

``````function calculateTotalAmount(p, r, t) {
return p * (1 + ((r/100) * t))
}
console.log(calculateTotalAmount(10000, 10, 1))``````

### Result:

``11000``

## Create a browser-based simple interest calculator

Let’s create an interactive calculator with the three input number fields (Principle, Rate of interest, Time in Years) and a button. On button click, total interest and amount will be displayed on the screen.

``````
<html>
<body>
<input type="number" id="p" placeholder="Enter Principle amount">
<input type="number" id="r" placeholder="Enter Rate of interest">
<input type="number" id="t" placeholder="Enter Time in Years">
<button id="calculate">Calculate</button>
<p id="result"></p>

<script>
function calculateInterest(p, r, t) {
return (p*r*t) / 100
}

function calculateTotalAmount(p, r, t) {
return p * (1 + ((r/100) * t))
}

function calculate() {
const p = document.querySelector("#p").value;
const r = document.querySelector("#r").value;
const t = document.querySelector("#t").value;

const interest = calculateInterest(p, r, t);
const total = calculateTotalAmount(p, r, t);
const result = `Interest: \$\${interest}, Total Amt: \$\${total}`;
document.querySelector("#result").innerHTML = result
} 